diff --git a/ChangeLog b/ChangeLog
index d8bc414359..e74fdecb45 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Mon Oct  7 22:52:16 2013  Akinori MUSHA  <knu@iDaemons.org>
+
+	* misc/ruby-additional.el: Use preceding-char/following-char
+	  (returning 0 at BOF/EOF) instead of char-before/char-after
+	  (returning nil at BOF/EOF) to avoid error from char-syntax when
+	  at BOF/EOF.
+
 Mon Oct  7 22:45:20 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* cont.c (FIBER_USE_NATIVE): split long conditions.
diff --git a/misc/ruby-additional.el b/misc/ruby-additional.el
index 6ef10944f2..85cfdd8d90 100644
--- a/misc/ruby-additional.el
+++ b/misc/ruby-additional.el
@@ -7,11 +7,11 @@
 
      (defun ruby-insert-end ()
        (interactive)
-       (if (eq (char-syntax (char-before)) ?w)
+       (if (eq (char-syntax (preceding-char)) ?w)
            (insert " "))
        (insert "end")
        (save-excursion
-         (if (eq (char-syntax (char-after)) ?w)
+         (if (eq (char-syntax (following-char)) ?w)
              (insert " "))
          (ruby-indent-line t)
          (end-of-line)))
@@ -19,16 +19,16 @@
      (defun ruby-brace-to-do-end ()
        (when (looking-at "{")
          (let ((orig (point)) (end (progn (ruby-forward-sexp) (point))))
-           (when (eq (char-before) ?\})
+           (when (eq (preceding-char) ?\})
              (delete-char -1)
-             (if (eq (char-syntax (char-before)) ?w)
+             (if (eq (char-syntax (preceding-char)) ?w)
                  (insert " "))
              (insert "end")
-             (if (eq (char-syntax (char-after)) ?w)
+             (if (eq (char-syntax (following-char)) ?w)
                  (insert " "))
              (goto-char orig)
              (delete-char 1)
-             (if (eq (char-syntax (char-before)) ?w)
+             (if (eq (char-syntax (preceding-char)) ?w)
                  (insert " "))
              (insert "do")
              (when (looking-at "\\sw\\||")
@@ -38,7 +38,7 @@
 
      (defun ruby-do-end-to-brace ()
        (when (and (or (bolp)
-                      (not (memq (char-syntax (char-before)) '(?w ?_))))
+                      (not (memq (char-syntax (preceding-char)) '(?w ?_))))
                   (looking-at "\\<do\\(\\s \\|$\\)"))
          (let ((orig (point)) (end (progn (ruby-forward-sexp) (point))))
            (backward-char 3)