A control device includes a PWM control unit that executes PWM control over an alternating-current motor mounted on a vehicle. The PWM control unit includes an alarm sound generation processing unit that executes an alarm sound generating process of generating an alarm sound from the motor for informing a pedestrian, or the like, of the approach of the vehicle by intentionally varying phase current flowing through the motor by periodically adding a variation value (ΔV) to a d-axis voltage command value (Vd) at a predetermined interval. At the time of executing the alarm sound generating process, the alarm sound generation processing unit adjusts the variation value (ΔV) such that the d-axis voltage command value (Vda) resulting from the alarm sound generating process (the sum of Vd and ΔV) falls within a range in which it is possible to suppress occurrence of an overcurrent in the motor.