PURPOSE: To reduce the energy loss in a running operation of a step-up regenerative coil required for a step-up regenerative operation in a chopper-controlled DC motor for a vehicle such as an electric vehicle or the like.

CONSTITUTION: A motor drive circuit is constituted in such a way that a series circuit composed of a first switching means 4 and of a diode 5 for regeneration is connected to an armature circuit 3 formed by connecting a coil 2 for step-up regeneration in series with an armature 1, that a second switching means 7 is connected in parallel with a flywheel diode 5 and that the first and second switching means are driven by a chopper control circuit 13. In the motor drive circuit, a step-up regenerative-braking control method is formed in such a way that the chopper control circuit 13 is changed over to a high frequency in a step-up regenerative operation and that the second switching means 7 is chopper- controlled.