The present invention relates to a motor drive apparatus and, more particularly, to a motor drive apparatus capable of immediately restarting by maintaining sensorless control during a stop operation of a motor. The motor drive apparatus comprises: an inverter for driving a motor by using an AC voltage; and a control unit for controlling operations of a switching element included in the inverter. At this time, when a stop command is input, the control unit decreases a duty ratio of a PWM signal until a present speed of the motor becomes smaller than a predetermined minimum speed, thereby decreasing the revolutions per minute of the motor. Then, when a restart command is input in a state where the duty ratio of the PWM signal is decreased, the control unit can immediately restart the motor by increasing the duty ratio of the PWM signal.