diff --git a/backend/apps/fields/admin.py b/backend/apps/fields/admin.py
index 8c38f3f..4f55bb1 100644
--- a/backend/apps/fields/admin.py
+++ b/backend/apps/fields/admin.py
@@ -1,3 +1,25 @@
 from django.contrib import admin
+from django.contrib.gis import admin as gis_admin
+from .models import OfficialKyosaiField, OfficialChusankanField, Field
 
-# Register your models here.
+
+@admin.register(OfficialKyosaiField)
+class OfficialKyosaiFieldAdmin(admin.ModelAdmin):
+    list_display = ('k_num', 's_num', 'kanji_name', 'address', 'area')
+    search_fields = ('k_num', 'kanji_name', 'address')
+    list_filter = ('s_num',)
+
+
+@admin.register(OfficialChusankanField)
+class OfficialChusankanFieldAdmin(admin.ModelAdmin):
+    list_display = ('c_id', 'oaza', 'aza', 'chiban', 'area', 'payment_amount')
+    search_fields = ('c_id', 'oaza', 'aza')
+    list_filter = ('oaza',)
+
+
+@admin.register(Field)
+class FieldAdmin(gis_admin.GISModelAdmin):
+    list_display = ('name', 'address', 'area_tan', 'area_m2', 'owner_name', 'kyosai_field', 'chusankan_field')
+    search_fields = ('name', 'address', 'owner_name')
+    list_filter = ('kyosai_field', 'chusankan_field')
+    gis_widget_kwargs = {'attrs': {'static_map': False, 'longitude': 139.0, 'latitude': 36.0, 'zoom': 10}}
diff --git a/backend/apps/fields/migrations/0001_initial.py b/backend/apps/fields/migrations/0001_initial.py
new file mode 100644
index 0000000..428635b
--- /dev/null
+++ b/backend/apps/fields/migrations/0001_initial.py
@@ -0,0 +1,65 @@
+# Generated by Django 5.0 on 2026-02-15 02:45
+
+import django.contrib.gis.db.models.fields
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='OfficialChusankanField',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('c_id', models.CharField(max_length=20, unique=True, verbose_name='中山間ID')),
+                ('oaza', models.CharField(max_length=100, verbose_name='大字')),
+                ('aza', models.CharField(max_length=100, verbose_name='字')),
+                ('chiban', models.CharField(max_length=50, verbose_name='地番')),
+                ('area', models.DecimalField(decimal_places=2, max_digits=10, verbose_name='面積(ha)')),
+                ('payment_amount', models.DecimalField(blank=True, decimal_places=0, max_digits=12, null=True, verbose_name='支払金額')),
+            ],
+            options={
+                'verbose_name': '中山間マスタ',
+                'verbose_name_plural': '中山間マスタ',
+            },
+        ),
+        migrations.CreateModel(
+            name='OfficialKyosaiField',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('k_num', models.CharField(max_length=20, unique=True, verbose_name='共済番号')),
+                ('s_num', models.CharField(blank=True, max_length=20, null=True, verbose_name='枝番')),
+                ('address', models.CharField(max_length=255, verbose_name='住所')),
+                ('kanji_name', models.CharField(max_length=100, verbose_name='漢字名')),
+                ('area', models.DecimalField(decimal_places=2, max_digits=10, verbose_name='面積(ha)')),
+            ],
+            options={
+                'verbose_name': '共済マスタ',
+                'verbose_name_plural': '共済マスタ',
+            },
+        ),
+        migrations.CreateModel(
+            name='Field',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100, verbose_name='圃場名')),
+                ('address', models.CharField(max_length=255, verbose_name='住所')),
+                ('area_tan', models.DecimalField(decimal_places=4, max_digits=6, verbose_name='面積(反)')),
+                ('area_m2', models.IntegerField(verbose_name='面積(m2)')),
+                ('owner_name', models.CharField(max_length=100, verbose_name='所有者名')),
+                ('location', django.contrib.gis.db.models.fields.PointField(blank=True, null=True, srid=4326, verbose_name='位置情報')),
+                ('chusankan_field', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='fields', to='fields.officialchusankanfield', verbose_name='関連中山間マスタ')),
+                ('kyosai_field', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='fields', to='fields.officialkyosaifield', verbose_name='関連共済マスタ')),
+            ],
+            options={
+                'verbose_name': '圃場',
+                'verbose_name_plural': '圃場',
+            },
+        ),
+    ]
diff --git a/backend/apps/fields/models.py b/backend/apps/fields/models.py
index 71a8362..eb48eaf 100644
--- a/backend/apps/fields/models.py
+++ b/backend/apps/fields/models.py
@@ -1,3 +1,65 @@
+from django.contrib.gis.db import models as gis_models
 from django.db import models
 
-# Create your models here.
+
+class OfficialKyosaiField(models.Model):
+    k_num = models.CharField(max_length=20, unique=True, verbose_name="共済番号")
+    s_num = models.CharField(max_length=20, blank=True, null=True, verbose_name="枝番")
+    address = models.CharField(max_length=255, verbose_name="住所")
+    kanji_name = models.CharField(max_length=100, verbose_name="漢字名")
+    area = models.DecimalField(max_digits=10, decimal_places=2, verbose_name="面積(ha)")
+
+    class Meta:
+        verbose_name = "共済マスタ"
+        verbose_name_plural = "共済マスタ"
+
+    def __str__(self):
+        return f"{self.k_num} ({self.kanji_name})"
+
+
+class OfficialChusankanField(models.Model):
+    c_id = models.CharField(max_length=20, unique=True, verbose_name="中山間ID")
+    oaza = models.CharField(max_length=100, verbose_name="大字")
+    aza = models.CharField(max_length=100, verbose_name="字")
+    chiban = models.CharField(max_length=50, verbose_name="地番")
+    area = models.DecimalField(max_digits=10, decimal_places=2, verbose_name="面積(ha)")
+    payment_amount = models.DecimalField(max_digits=12, decimal_places=0, blank=True, null=True, verbose_name="支払金額")
+
+    class Meta:
+        verbose_name = "中山間マスタ"
+        verbose_name_plural = "中山間マスタ"
+
+    def __str__(self):
+        return f"{self.c_id} ({self.oaza}{self.aza})"
+
+
+class Field(models.Model):
+    name = models.CharField(max_length=100, verbose_name="圃場名")
+    address = models.CharField(max_length=255, verbose_name="住所")
+    area_tan = models.DecimalField(max_digits=6, decimal_places=4, verbose_name="面積(反)")
+    area_m2 = models.IntegerField(verbose_name="面積(m2)")
+    owner_name = models.CharField(max_length=100, verbose_name="所有者名")
+    kyosai_field = models.ForeignKey(
+        OfficialKyosaiField,
+        on_delete=models.SET_NULL,
+        blank=True,
+        null=True,
+        related_name='fields',
+        verbose_name="関連共済マスタ"
+    )
+    chusankan_field = models.ForeignKey(
+        OfficialChusankanField,
+        on_delete=models.SET_NULL,
+        blank=True,
+        null=True,
+        related_name='fields',
+        verbose_name="関連中山間マスタ"
+    )
+    location = gis_models.PointField(blank=True, null=True, verbose_name="位置情報")
+
+    class Meta:
+        verbose_name = "圃場"
+        verbose_name_plural = "圃場"
+
+    def __str__(self):
+        return self.name
diff --git a/backend/apps/plans/admin.py b/backend/apps/plans/admin.py
index 8c38f3f..72c2ef6 100644
--- a/backend/apps/plans/admin.py
+++ b/backend/apps/plans/admin.py
@@ -1,3 +1,23 @@
 from django.contrib import admin
+from .models import Crop, Variety, Plan
 
-# Register your models here.
+
+@admin.register(Crop)
+class CropAdmin(admin.ModelAdmin):
+    list_display = ('name',)
+    search_fields = ('name',)
+
+
+@admin.register(Variety)
+class VarietyAdmin(admin.ModelAdmin):
+    list_display = ('crop', 'name')
+    search_fields = ('name', 'crop__name')
+    list_filter = ('crop',)
+
+
+@admin.register(Plan)
+class PlanAdmin(admin.ModelAdmin):
+    list_display = ('field', 'year', 'crop', 'variety', 'notes')
+    search_fields = ('field__name', 'crop__name', 'variety__name')
+    list_filter = ('year', 'crop')
+    ordering = ('-year', 'field')
diff --git a/backend/apps/plans/migrations/0001_initial.py b/backend/apps/plans/migrations/0001_initial.py
new file mode 100644
index 0000000..52cd30b
--- /dev/null
+++ b/backend/apps/plans/migrations/0001_initial.py
@@ -0,0 +1,57 @@
+# Generated by Django 5.0 on 2026-02-15 02:45
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ('fields', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Crop',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100, unique=True, verbose_name='作物名')),
+            ],
+            options={
+                'verbose_name': '作物マスタ',
+                'verbose_name_plural': '作物マスタ',
+            },
+        ),
+        migrations.CreateModel(
+            name='Variety',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100, verbose_name='品種名')),
+                ('crop', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='varieties', to='plans.crop', verbose_name='作物')),
+            ],
+            options={
+                'verbose_name': '品種マスタ',
+                'verbose_name_plural': '品種マスタ',
+                'unique_together': {('crop', 'name')},
+            },
+        ),
+        migrations.CreateModel(
+            name='Plan',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('year', models.IntegerField(verbose_name='作付年度')),
+                ('notes', models.TextField(blank=True, null=True, verbose_name='備考')),
+                ('crop', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='plans', to='plans.crop', verbose_name='作物')),
+                ('field', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='plans', to='fields.field', verbose_name='圃場')),
+                ('variety', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='plans', to='plans.variety', verbose_name='品種')),
+            ],
+            options={
+                'verbose_name': '作付け計画',
+                'verbose_name_plural': '作付け計画',
+                'ordering': ['-year', 'field'],
+                'unique_together': {('field', 'year')},
+            },
+        ),
+    ]
diff --git a/backend/apps/plans/models.py b/backend/apps/plans/models.py
index 71a8362..2521baf 100644
--- a/backend/apps/plans/models.py
+++ b/backend/apps/plans/models.py
@@ -1,3 +1,43 @@
 from django.db import models
+from apps.fields.models import Field
 
-# Create your models here.
+
+class Crop(models.Model):
+    name = models.CharField(max_length=100, unique=True, verbose_name="作物名")
+
+    class Meta:
+        verbose_name = "作物マスタ"
+        verbose_name_plural = "作物マスタ"
+
+    def __str__(self):
+        return self.name
+
+
+class Variety(models.Model):
+    crop = models.ForeignKey(Crop, on_delete=models.CASCADE, related_name='varieties', verbose_name="作物")
+    name = models.CharField(max_length=100, verbose_name="品種名")
+
+    class Meta:
+        verbose_name = "品種マスタ"
+        verbose_name_plural = "品種マスタ"
+        unique_together = [['crop', 'name']]
+
+    def __str__(self):
+        return f"{self.crop.name} - {self.name}"
+
+
+class Plan(models.Model):
+    field = models.ForeignKey(Field, on_delete=models.CASCADE, related_name='plans', verbose_name="圃場")
+    year = models.IntegerField(verbose_name="作付年度")
+    crop = models.ForeignKey(Crop, on_delete=models.CASCADE, related_name='plans', verbose_name="作物")
+    variety = models.ForeignKey(Variety, on_delete=models.CASCADE, related_name='plans', verbose_name="品種")
+    notes = models.TextField(blank=True, null=True, verbose_name="備考")
+
+    class Meta:
+        verbose_name = "作付け計画"
+        verbose_name_plural = "作付け計画"
+        unique_together = [['field', 'year']]
+        ordering = ['-year', 'field']
+
+    def __str__(self):
+        return f"{self.field.name} - {self.year} - {self.crop.name}"