A vehicle acceleration suppression device and a vehicle acceleration suppression method are provided to be capable of suppressing a degradation in a drive performance and suppressing acceleration at the time of an incorrect manipulation of an accelerator, at the time of parking. Based on a parking frame certainty degree indicative of a degree of certainty that there is a parking frame in a vehicle travel direction and a parking frame entering certainty degree indicative of a degree of certainty that the vehicle enters the parking frame, a total certainty degree indicative of a total degree of certainty of the parking frame certainty degree and the parking frame entering certainty degree is set. As the total certainty degree is higher, a suppression degree of the vehicle acceleration to be controlled in response to a manipulation amount of an accelerator pedal manipulated by a driver to instruct a drive force is increased.