diff --git a/encode_test.go b/encode_test.go
index 59bb08f..1c0de3c 100644
--- a/encode_test.go
+++ b/encode_test.go
@@ -2406,3 +2406,21 @@ func TestIssue339(t *testing.T) {
 		t.Errorf("unexpected result: %v != %v", got, expected)
 	}
 }
+
+func TestIssue376(t *testing.T) {
+	type Container struct {
+		V interface{} `json:"value"`
+	}
+	type MapOnly struct {
+		Map map[string]int64 `json:"map"`
+	}
+	b, err := json.Marshal(Container{MapOnly{}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	got := string(b)
+	expected := `{"value":{"map":null}}`
+	if got != expected {
+		t.Errorf("unexpected result: %v != %v", got, expected)
+	}
+}
diff --git a/internal/cmd/generator/vm.go.tmpl b/internal/cmd/generator/vm.go.tmpl
index 91b11e1..645d20f 100644
--- a/internal/cmd/generator/vm.go.tmpl
+++ b/internal/cmd/generator/vm.go.tmpl
@@ -3,6 +3,7 @@ package vm
 
 import (
 	"math"
+	"reflect"
 	"sort"
 	"unsafe"
 
@@ -194,9 +195,12 @@ func Run(ctx *encoder.RuntimeContext, b []byte, codeSet *encoder.OpcodeSet) ([]b
 				typ = iface.typ
 			}
 			if ifacePtr == nil {
-				b = appendNullComma(ctx, b)
-				code = code.Next
-				break
+				isDirectedNil := typ != nil && typ.Kind() == reflect.Struct && !runtime.IfaceIndir(typ)
+				if !isDirectedNil {
+					b = appendNullComma(ctx, b)
+					code = code.Next
+					break
+				}
 			}
 			ctx.KeepRefs = append(ctx.KeepRefs, up)
 			ifaceCodeSet, err := encoder.CompileToGetCodeSet(ctx, uintptr(unsafe.Pointer(typ)))
diff --git a/internal/encoder/vm/vm.go b/internal/encoder/vm/vm.go
index 91b11e1..645d20f 100644
--- a/internal/encoder/vm/vm.go
+++ b/internal/encoder/vm/vm.go
@@ -3,6 +3,7 @@ package vm
 
 import (
 	"math"
+	"reflect"
 	"sort"
 	"unsafe"
 
@@ -194,9 +195,12 @@ func Run(ctx *encoder.RuntimeContext, b []byte, codeSet *encoder.OpcodeSet) ([]b
 				typ = iface.typ
 			}
 			if ifacePtr == nil {
-				b = appendNullComma(ctx, b)
-				code = code.Next
-				break
+				isDirectedNil := typ != nil && typ.Kind() == reflect.Struct && !runtime.IfaceIndir(typ)
+				if !isDirectedNil {
+					b = appendNullComma(ctx, b)
+					code = code.Next
+					break
+				}
 			}
 			ctx.KeepRefs = append(ctx.KeepRefs, up)
 			ifaceCodeSet, err := encoder.CompileToGetCodeSet(ctx, uintptr(unsafe.Pointer(typ)))
diff --git a/internal/encoder/vm_color/vm.go b/internal/encoder/vm_color/vm.go
index 5c6c52c..a63e83e 100644
--- a/internal/encoder/vm_color/vm.go
+++ b/internal/encoder/vm_color/vm.go
@@ -3,6 +3,7 @@ package vm_color
 
 import (
 	"math"
+	"reflect"
 	"sort"
 	"unsafe"
 
@@ -194,9 +195,12 @@ func Run(ctx *encoder.RuntimeContext, b []byte, codeSet *encoder.OpcodeSet) ([]b
 				typ = iface.typ
 			}
 			if ifacePtr == nil {
-				b = appendNullComma(ctx, b)
-				code = code.Next
-				break
+				isDirectedNil := typ != nil && typ.Kind() == reflect.Struct && !runtime.IfaceIndir(typ)
+				if !isDirectedNil {
+					b = appendNullComma(ctx, b)
+					code = code.Next
+					break
+				}
 			}
 			ctx.KeepRefs = append(ctx.KeepRefs, up)
 			ifaceCodeSet, err := encoder.CompileToGetCodeSet(ctx, uintptr(unsafe.Pointer(typ)))
diff --git a/internal/encoder/vm_color_indent/vm.go b/internal/encoder/vm_color_indent/vm.go
index 42dc11c..3b4e22e 100644
--- a/internal/encoder/vm_color_indent/vm.go
+++ b/internal/encoder/vm_color_indent/vm.go
@@ -3,6 +3,7 @@ package vm_color_indent
 
 import (
 	"math"
+	"reflect"
 	"sort"
 	"unsafe"
 
@@ -194,9 +195,12 @@ func Run(ctx *encoder.RuntimeContext, b []byte, codeSet *encoder.OpcodeSet) ([]b
 				typ = iface.typ
 			}
 			if ifacePtr == nil {
-				b = appendNullComma(ctx, b)
-				code = code.Next
-				break
+				isDirectedNil := typ != nil && typ.Kind() == reflect.Struct && !runtime.IfaceIndir(typ)
+				if !isDirectedNil {
+					b = appendNullComma(ctx, b)
+					code = code.Next
+					break
+				}
 			}
 			ctx.KeepRefs = append(ctx.KeepRefs, up)
 			ifaceCodeSet, err := encoder.CompileToGetCodeSet(ctx, uintptr(unsafe.Pointer(typ)))
diff --git a/internal/encoder/vm_indent/vm.go b/internal/encoder/vm_indent/vm.go
index dfe0cc6..836c5c8 100644
--- a/internal/encoder/vm_indent/vm.go
+++ b/internal/encoder/vm_indent/vm.go
@@ -3,6 +3,7 @@ package vm_indent
 
 import (
 	"math"
+	"reflect"
 	"sort"
 	"unsafe"
 
@@ -194,9 +195,12 @@ func Run(ctx *encoder.RuntimeContext, b []byte, codeSet *encoder.OpcodeSet) ([]b
 				typ = iface.typ
 			}
 			if ifacePtr == nil {
-				b = appendNullComma(ctx, b)
-				code = code.Next
-				break
+				isDirectedNil := typ != nil && typ.Kind() == reflect.Struct && !runtime.IfaceIndir(typ)
+				if !isDirectedNil {
+					b = appendNullComma(ctx, b)
+					code = code.Next
+					break
+				}
 			}
 			ctx.KeepRefs = append(ctx.KeepRefs, up)
 			ifaceCodeSet, err := encoder.CompileToGetCodeSet(ctx, uintptr(unsafe.Pointer(typ)))