A PWM-signal-output circuit includes a first output unit to output a PWM signal with a first duty cycle, in a first period in which a motor starts rotating, a second output unit to output the PWM signal whose duty cycle increases toward a second duty cycle and decreases from the second duty cycle in a period from a logic level change in speed signal until its subsequent logic level change, in a second period following the first, the speed signal having a period corresponding to a motor-rotation speed and a logic level changing alternately, and a third output unit to output the PWM signal whose duty cycle increases toward that of the input signal and thereafter decreases from that of the input signal in a period from a logic level change in the speed signal until its subsequent logic level change, after the second period elapses.