A motor drive controlling apparatus comprising: a controller that generates a drive control signal in response to input of a speed command signal wherein the speed command signal is a pulse signal, with the number of pulses of the pulse signal corresponding to the number of rotation steps and the number of pulses per unit time corresponding to a first rotational speed; and a motor driver that generates a drive signal in response to input of the drive control signal and outputs the drive signal to a motor, wherein the controller repeatedly generates the drive control signal in a period during which the speed command signal is inputted and stops generating the drive control signal in a period during which the speed command signal is not inputted to repeat an operation period in which the motor performs rotational operation and a stop period in which the motor stops operating in a non-excited state; wherein the controller repeats the operation period and the stop period to set the rotational speed of the motor per rotation at a second rotational speed lower than the first rotational speed corresponding to the speed command signal; wherein a length of the operation period and a length of the stop period are set based on a ratio between the first rotational speed and the second rotational speed; characterized by adjustment of the length of the operation period and the length of the stop period allowing the motor to perform rotational operation at the second rotational speed that is a desired rotational speed and is lower than the lower-limit rotational speed of the rotating shaft of the motor and lower than specified in the specifications of the motor. a controller that generates a drive control signal in response to input of a speed command signal wherein the speed command signal is a pulse signal, with the number of pulses of the pulse signal corresponding to the number of rotation steps and the number of pulses per unit time corresponding to a first rotational speed; and a motor driver that generates a drive signal in response to input of the drive control signal and outputs the drive signal to a motor, wherein the controller repeatedly generates the drive control signal in a period during which the speed command signal is inputted and stops generating the drive control signal in a period during which the speed command signal is not inputted to repeat an operation period in which the motor performs rotational operation and a stop period in which the motor stops operating in a non-excited state; wherein the controller repeats the operation period and the stop period to set the rotational speed of the motor per rotation at a second rotational speed lower than the first rotational speed corresponding to the speed command signal; wherein a length of the operation period and a length of the stop period are set based on a ratio between the first rotational speed and the second rotational speed; characterized by adjustment of the length of the operation period and the length of the stop period allowing the motor to perform rotational operation at the second rotational speed that is a desired rotational speed and is lower than the lower-limit rotational speed of the rotating shaft of the motor and lower than specified in the specifications of the motor.