To prevent wasteful consumption of energy during acceleration of a motor or inertial traveling, and to calculate a vehicle speed from a rotation speed of the motor without a sensor for detecting an actual vehicle speed.

This control method for a vehicle with a motor assist function provided with a human power drive system and an electric drive system in parallel generates an electric power drive force TM depending on human power drive force TP on the basis of a prescribed assist rate characteristic changing a ratio of the electric power drive force TM to the human power drive force TP according to the vehicle speed VSP. A motive power source of the electric drive system comprises the electric motor. When the human power drive force TP is below a lower limit value TPL, an assist rotation current iID is supplied to maintain a rotation speed v of the motor corresponding to the vehicle speed VSP at the time. When a prescribed assist stop condition set on the basis of the human drive force TP and the rotation speed v of the motor is satisfied, the assist rotation current iID is shut off.