diff --git a/src/Nirum/Targets/Python.hs b/src/Nirum/Targets/Python.hs
index e9af30c..d4fc7f9 100644
--- a/src/Nirum/Targets/Python.hs
+++ b/src/Nirum/Targets/Python.hs
@@ -21,7 +21,7 @@ module Nirum.Targets.Python
 
 import Control.Monad (forM)
 import qualified Data.List as L
-import Data.Maybe (catMaybes, fromMaybe)
+import Data.Maybe (catMaybes, fromMaybe, isJust)
 import GHC.Exts (IsList (toList))
 import Text.Printf (printf)
 
@@ -462,13 +462,32 @@ compileTypeDeclaration src d@TypeDeclaration { typename = typename'
     |]
 compileTypeDeclaration src d@TypeDeclaration { typename = typename'
                                              , type' = UnboxedType itype
+                                             , typeAnnotations = annots
                                              } = do
     let className = toClassName' typename'
     itypeExpr <- compileTypeExpression' src (Just itype)
     insertStandardImport "typing"
     insertThirdPartyImports [("nirum.deserialize", ["deserialize_meta"])]
     pyVer <- getPythonVersion
-    Validator typePred valueValidators' <- compileValidator' src itype "value"
+    Validator typePred valueValidatorsProto <-
+        compileValidator' src itype "value"
+    valueValidators' <- case A.lookup "numeric-constraints" annots of
+        Just A.Annotation { A.arguments = args } -> do
+            let constraintValidators =
+                    [ case name' of
+                          "min" -> Just $ ValueValidator
+                                       [qq|value >= ($value)|]
+                                       [qq|value is less than $value|]
+                          "max" -> Just $ ValueValidator
+                                       [qq|value <= ($value)|]
+                                       [qq|value is greater than $value|]
+                          _ -> Nothing
+                    | (name', value) <- toList args
+                    ]
+            if all isJust constraintValidators
+            then return $ catMaybes constraintValidators
+            else fail "Unsupported arguments on @numeric-constraints"
+        Nothing -> return valueValidatorsProto
     return $ toStrict $ renderMarkup $ [compileText|
 class #{className}(object):
 #{compileDocstring "    " d}
diff --git a/test/Nirum/Targets/PythonSpec.hs b/test/Nirum/Targets/PythonSpec.hs
index c4aaf43..add8362 100644
--- a/test/Nirum/Targets/PythonSpec.hs
+++ b/test/Nirum/Targets/PythonSpec.hs
@@ -7,8 +7,10 @@ import System.FilePath ((</>))
 import Test.Hspec.Meta
 import Text.InterpolatedString.Perl6 (q)
 
+import qualified Nirum.Constructs.Annotation as A
 import Nirum.Constructs.Module (Module (Module))
 import Nirum.Constructs.Name (Name (Name))
+import Nirum.Constructs.TypeDeclaration
 import Nirum.Package.Metadata (Target (compilePackage))
 import Nirum.Targets.Python
     ( Source (Source)
@@ -169,3 +171,16 @@ spec = do
         parseModulePath "foo..bar" `shouldBe` Nothing
         parseModulePath "foo.bar>" `shouldBe` Nothing
         parseModulePath "foo.bar-" `shouldBe` Nothing
+
+    describe "@numeric-constraints" $
+        it "fails if unsupported arguments are present" $ do
+            let Right annots = A.fromList
+                    [ A.Annotation "numeric-constraints"
+                                   [("min", "1"), ("unsupported", "asdf")]
+                    ]
+            let unboxed = TypeDeclaration "foo" (UnboxedType "int32") annots
+            let (Source pkg _) = makeDummySource $ Module [unboxed] Nothing
+            let files = compilePackage pkg
+            let result = M.lookup ("src" </> "foo" </> "__init__.py") files
+            result `shouldBe`
+                Just (Left "Unsupported arguments on @numeric-constraints")
diff --git a/test/nirum_fixture/fixture/constraints.nrm b/test/nirum_fixture/fixture/constraints.nrm
new file mode 100644
index 0000000..376d351
--- /dev/null
+++ b/test/nirum_fixture/fixture/constraints.nrm
@@ -0,0 +1,2 @@
+@numeric-constraints(min="1", max="12")
+unboxed month (int32);
diff --git a/test/python/constraints_test.py b/test/python/constraints_test.py
new file mode 100644
index 0000000..a46ee1e
--- /dev/null
+++ b/test/python/constraints_test.py
@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+
+from pytest import raises
+
+from fixture.constraints import Month
+
+
+def test_numeric_constraints():
+    month = Month(1)
+    assert month.value == 1
+
+    with raises(ValueError):
+        Month(0)
+
+    with raises(ValueError):
+        Month(13)
diff --git a/test/python/setup_test.py b/test/python/setup_test.py
index f09c07f..0a6a4bb 100644
--- a/test/python/setup_test.py
+++ b/test/python/setup_test.py
@@ -22,7 +22,7 @@ def test_setup_metadata():
     assert set(pkg['Provides']) == {
         'fixture', 'fixture.foo', 'fixture.foo.bar', 'fixture.qux',
         'fixture.reserved_keyword_enum', 'fixture.reserved_keyword_union',
-        'fixture.types', 'fixture.alias',
+        'fixture.types', 'fixture.alias', 'fixture.constraints',
         'renamed', 'renamed.foo', 'renamed.foo.bar',
     }
     assert ['0.3.0'] == pkg['Version']
@@ -43,6 +43,7 @@ def test_module_entry_points():
         'fixture.reserved-keyword-enum', 'fixture.reserved-keyword-union',
         'fixture.types',
         'fixture.alias',
+        'fixture.constraints',
         'renames.test.foo', 'renames.test.foo.bar',
     }
     import fixture.foo