Based on a parking frame certainty degree indicative of a degree of certainty about a presence is a parking frame in the travel direction of the vehicle and a parking frame entering certainty degree indicative of a degree of certainty about whether the vehicle enters the parking frame, a total certainty degree indicative of a total degree of the certainty of the parking frame certainty degree and the parking frame entering certainty degree is calculated. Acceleration of the vehicle is controlled depending on a manipulation amount of an accelerator pedal manipulated by a drive to instruct a driving force and is suppressed in a lower suppression degree when the total certainty degree is lower than when the total certainty degree is higher. Furthermore, the acceleration of the vehicle is suppressed in the suppression degree decreased depending on the travel direction of the vehicle.