diff --git a/scrapy/http/request/__init__.py b/scrapy/http/request/__init__.py
index b9c5f8541..13a92ffa0 100644
--- a/scrapy/http/request/__init__.py
+++ b/scrapy/http/request/__init__.py
@@ -28,9 +28,9 @@ class Request(object_ref):
         self.priority = priority
 
         if callback is not None and not callable(callback):
-            raise TypeError('callback must be a function, got %s' % type(callback).__name__)
+            raise TypeError('callback must be a callable, got %s' % type(callback).__name__)
         if errback is not None and not callable(errback):
-            raise TypeError('errback must be a function, got %s' % type(errback).__name__)
+            raise TypeError('errback must be a callable, got %s' % type(errback).__name__)
         assert callback or not errback, "Cannot use errback without a callback"
         self.callback = callback
         self.errback = errback