Abstract: An automatic speed stage changing apparatus for a wheel loader is intended to control shift-down of the wheel loader when a bucket is caused to plunge into an object to be digged such as a hill-shaped earth mass or the like, and an angle suitable for digging work is previously set with respect to a boom angle and a bucket angle respectively. When both the boom and the bucket assume said set angle during forward movement toward the hill-shaped earth mass, this is detected and thereafter a speed stage is automatically shifted down from the selected existent speed stage to a lower speed stage at which a tractive force is increased in accordance with an output of said detection.