Disclosed is a control method and a control apparatus (7) for controlling a PWM inverter (2). The PWM inverter receives AC power and generates an AC output having a controlled frequency to be supplied to an AC motor (3). A circuit (8, 9) is provided for generating, on the basis of a given running command (ω*), a PWM signal controlling the inverter with a given sampling period, and a further circuit (10) controls the PWM signal generating circuit, whereby the AC motor generates an electromagnetic tone preselected so as to correspond to desired information when the AC motor is driven by output of the inverter controlled by the PWM signal. The above described desired information may be information representing the running state of the motor or selected music.