diff --git a/src/operator/instance_norm.cc b/src/operator/instance_norm.cc
index 00482b52d034..abce4140e499 100644
--- a/src/operator/instance_norm.cc
+++ b/src/operator/instance_norm.cc
@@ -60,7 +60,7 @@ the input using the following formula:
 
 .. math::
 
-  out = \frac{x - mean[data]}{ \sqrt{Var[data]} + \epsilon} * gamma + beta
+  out = \frac{x - mean[data]}{ \sqrt{Var[data] + \epsilon}} * gamma + beta
 
 This layer is similar to batch normalization layer (`BatchNorm`)
 with two differences: first, the normalization is