diff --git a/README.md b/README.md
index b063a11..0a4b57e 100644
--- a/README.md
+++ b/README.md
@@ -24,9 +24,9 @@ extensions = [
 
 You can use d2lang in sphinx directive
 
-`source/index.rst`
+`source/index.rest`
 
-```rst
+```rest
 Hello World
 ===========
 
@@ -40,7 +40,7 @@ Hello World
 
 You can use an external file like this
 
-```rst
+```rest
 Hello World
 ===========
 
@@ -59,7 +59,7 @@ There is two options you can use
 
 You can specify layout engine to use
 
-```rst
+```rest
 Hello World
 ===========
 
@@ -71,7 +71,7 @@ Hello World
 
 #### Output filename
 
-```rst
+```rest
 Hello World
 ===========