To reduce a processing load of a motor control device, by securely switching from a PWM control to a rectangular wave control in a high revolution range.

The motor control device includes: an inverter for converting a DC voltage from a DC power supply into an AC voltage, to supply to a motor; control means for drive controlling at least by turning on and off a switching element configuring the inverter so as to switch between the PWM control for the PWM drive of the motor and the rectangular wave control for the rectangular drive thereof; processing load discrimination means for discriminating whether or not the processing load by the control means during the execution of the PWM control becomes a predetermined value or larger; and on discrimination of the processing load having a predetermined value or larger, input voltage restriction means for decreasing the AC voltage to be input to the inverter.