This motor drive device 100 which converts a direct current into a three-phase alternating current and drives a motor 8 which is a three-phase motor is characterized by being provided with: inverter modules 5, 6, 7 wherein the number of inverter modules 5, 6, 7 provided is the same as the number of phases of the motor 8; and a control unit 9 which generates PWM signals for PWM driving of the inverter modules 5, 6, 7. The inverter modules 5, 6, 7 are each provided with multiple switching elements pairs each comprising two switching elements that are serially connected, said multiple switching elements pairs being connected in parallel with one another.