A constant current control power supply of an embodiment of the present invention includes a switching regulator that includes a switching circuit having a switching device and a rectifier device, a smoothing circuit having reactors and capacitors, a current detection circuit, and a control circuit, for outputting a constant current in accordance with a command value from a controller. When ON indicates a case where the command value commands an output of a higher current than a predetermined value and OFF indicates a case where the command value commands an output of a lower current than the predetermined value, on condition that a pulse operation alternating between the ON and the OFF is inputted, the control circuit amplifies a variation in the command value by a predetermined amplification factor and adds the amplified variation to the command value, and attenuates the added variation with a predetermined time constant.