PURPOSE: To obtain a system with a high power factor and efficiency by controlling a DC voltage and a power supply power factor with a period conduction rate in a PAM control electric motor drive device with a booster circuit as a base.

CONSTITUTION: This device is constituted of an AC power supply 1, a rectifier circuit 2, an inductor 3, a switching element 1 for flowing a short-circuiting current with a higher frequency than the power supply frequency of an AC power supply to the inductor, an AC-DC conversion part 5, an inverter 11, an electric motor 12, and a converter control part 13 for controlling the AC-DC conversion part 5 so that the DC output voltage matches the DC voltage command value according to the speed command value of the electric motor. With a converter control part 13, one cycle of a power supply frequency is classified into a conduction period corresponding to the section where a current value is low and a non-conduction period corresponding to the section where the current value is high, a switching element 4 is turned on during conduction period, and it is turned off during non-conduction period.