To suppress unbalance in chopping loss in a pair of switching elements of an electric motor.

In the chopping device for performing hard chopping, the control means delays the other on/off or off/on for on/off or off/on corresponding to one conduction instruction signal of first and second switching means, and furthermore, a switching means for previously performing on/off or off/on and another switching means for subsequently performing on/off or off/on are alternatively changed over.