To improve the discharge efficiency of regenerative energy and further to raise the reliability on a controller.

A chopper for regenerative power consumption, which speed-variably controls a motor 1 by a power converter 3 using a battery 4 as a DC power source and discharges electricity to a discharge resistor 5E by the ON control of a discharge transistor 5D when the terminal voltage of a battery gets over a set value by the regenerative power from a motor, continues the ON state for a certain time once after turning on the discharge transistor. It includes variably controlling the ON time of the discharge transistor, based on the temperature and the current of the battery or the discharge resistor.