diff --git a/src/doc/book/error-handling.md b/src/doc/book/error-handling.md
index 600019bcceb..e37360a457b 100644
--- a/src/doc/book/error-handling.md
+++ b/src/doc/book/error-handling.md
@@ -1643,7 +1643,7 @@ fn main() {
 
     let matches = match opts.parse(&args[1..]) {
         Ok(m)  => { m }
-		Err(e) => { panic!(e.to_string()) }
+        Err(e) => { panic!(e.to_string()) }
     };
 
     if matches.opt_present("h") {