diff --git a/ChangeLog b/ChangeLog
index 7a33e7a23e..7463660f63 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Thu Mar 29 10:12:12 2012  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* thread.c (rb_threadptr_execute_interrupts_common): use defined
+	  TIME_QUANTUM_USEC instead of a magic number.  there is no meanings
+	  to use different values for checking interval of interruption and
+	  thread switching limits.
+	  cf. [Bug #6098]
+
 Thu Mar 29 09:26:17 2012  Martin Bosslet  <Martin.Bosslet@googlemail.com>
 
 	* test/openssl/test_x509cert.rb: Exclude test that fails when issuing
diff --git a/thread.c b/thread.c
index 55ba49d62b..1fcdf824f9 100644
--- a/thread.c
+++ b/thread.c
@@ -1312,7 +1312,7 @@ rb_threadptr_execute_interrupts_common(rb_thread_t *th)
 	}
 
 	if (timer_interrupt) {
-	    unsigned long limits_us = 250 * 1000;
+	    unsigned long limits_us = TIME_QUANTUM_USEC;
 
 	    if (th->priority > 0)
 		limits_us <<= th->priority;