diff --git a/include/nncase/ir/op_utils.h b/include/nncase/ir/op_utils.h
index d4eaf65d7f..0f379661d5 100644
--- a/include/nncase/ir/op_utils.h
+++ b/include/nncase/ir/op_utils.h
@@ -385,6 +385,13 @@ inline bool is_simple_slice(const axis_t &begin, const axis_t &end, const axis_t
     return is_simple_slice;
 }
 
+inline shape_t get_instancenorm_const_shape(const shape_t &in_shape)
+{
+    shape_t const_shape(in_shape.size() - 1, 1);
+    const_shape[0] = in_shape[1];
+    return const_shape;
+}
+
 inline bool is_axis0_squeeze_or_expand_dim_bitcast(const shape_t &in_shape, const shape_t &out_shape)
 {
     auto in_begin = std::find_if_not(in_shape.begin(), in_shape.end(), [](size_t dim) { return dim == 1; });
diff --git a/src/ir/ops/instancenorm.cpp b/src/ir/ops/instancenorm.cpp
index a6803fd246..7d20bb0add 100644
--- a/src/ir/ops/instancenorm.cpp
+++ b/src/ir/ops/instancenorm.cpp
@@ -23,8 +23,8 @@ instancenorm::instancenorm(datatype_t input_type, shape_t input_shape, float eps
     : epsilon_(epsilon)
 {
     add_input("input", input_type, input_shape);
-    add_input("scale", input_type, shape_t { input_shape[1], 1, 1 });
-    add_input("bias", input_type, shape_t { input_shape[1], 1, 1 });
+    add_input("scale", input_type, get_instancenorm_const_shape(input_shape));
+    add_input("bias", input_type, get_instancenorm_const_shape(input_shape));
     add_output("output", input_type, input_shape);
 }