diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index f3d3c29fbc..c5a7f052db 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -474,7 +474,7 @@ VALUE rb_thread_wakeup(VALUE);
 VALUE rb_thread_wakeup_alive(VALUE);
 VALUE rb_thread_run(VALUE);
 VALUE rb_thread_kill(VALUE);
-VALUE rb_thread_create(VALUE (*)(ANYARGS), void*);
+VALUE rb_thread_create(VALUE (*)(void *), void*);
 int rb_thread_fd_select(int, rb_fdset_t *, rb_fdset_t *, rb_fdset_t *, struct timeval *);
 void rb_thread_wait_for(struct timeval);
 VALUE rb_thread_current(void);
diff --git a/thread.c b/thread.c
index db4326bd31..57ccfef8b7 100644
--- a/thread.c
+++ b/thread.c
@@ -810,7 +810,7 @@ thread_start_func_2(rb_thread_t *th, VALUE *stack_start)
 }
 
 static VALUE
-thread_create_core(VALUE thval, VALUE args, VALUE (*fn)(ANYARGS))
+thread_create_core(VALUE thval, VALUE args, VALUE (*fn)(void *))
 {
     rb_thread_t *th = rb_thread_ptr(thval), *current_th = GET_THREAD();
     int err;
@@ -944,7 +944,7 @@ thread_initialize(VALUE thread, VALUE args)
 }
 
 VALUE
-rb_thread_create(VALUE (*fn)(ANYARGS), void *arg)
+rb_thread_create(VALUE (*fn)(void *), void *arg)
 {
     return thread_create_core(rb_thread_alloc(rb_cThread), (VALUE)arg, fn);
 }
diff --git a/thread_pthread.c b/thread_pthread.c
index 39c3ed0ed4..cbe6aa028a 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -2156,7 +2156,7 @@ timer_pthread_fn(void *p)
 #endif /* UBF_TIMER_PTHREAD */
 
 static VALUE
-ubf_caller(const void *ignore)
+ubf_caller(void *ignore)
 {
     rb_thread_sleep_forever();
 
diff --git a/vm_core.h b/vm_core.h
index 74700f37f0..cb22fc4115 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -975,7 +975,7 @@ typedef struct rb_thread_struct {
             VALUE args;
         } proc;
         struct {
-            VALUE (*func)(ANYARGS);
+            VALUE (*func)(void *);
             void *arg;
         } func;
     } invoke_arg;