A motor drive controlling apparatus adapted to control a motor used in a tube pump comprising: a controller that generates and outputs a drive control signal, in response to an input of a speed command signal and a rotational direction signal, wherein the drive control signal includes a pulse width modulation (PWM) signal; a motor driver that generates a drive signal and outputs the generated drive signal to a motor , in response to an input of the drive control signal; and a position detector that detects a rotational position of the motor and outputs a detection signal that is based on a detection result, characterised in that the controller includes: a measurement unit that detects, based on the detection signal, a time point at which a rotation of the motor is, caused by an external factor, switched into a reverse direction that is reverse to a target rotational direction while the speed command signal and the rotational direction signal are being input, and measures, as the movement amount, a movement amount of the motor in the reverse direction from a rotational position of the motor at the time point at which the rotation of the motor is switched into the reverse direction, based on the detection signal; and a transmitting unit that transmits a stop control signal to the motor driver for stopping an output of the drive signal to the motor , when the movement amount is a predetermined first movement amount or more and a duty ratio of the PWM signal is a predetermined first duty ratio or more. a controller that generates and outputs a drive control signal, in response to an input of a speed command signal and a rotational direction signal, wherein the drive control signal includes a pulse width modulation (PWM) signal; a motor driver that generates a drive signal and outputs the generated drive signal to a motor , in response to an input of the drive control signal; and a position detector that detects a rotational position of the motor and outputs a detection signal that is based on a detection result, characterised in that the controller includes: a measurement unit that detects, based on the detection signal, a time point at which a rotation of the motor is, caused by an external factor, switched into a reverse direction that is reverse to a target rotational direction while the speed command signal and the rotational direction signal are being input, and measures, as the movement amount, a movement amount of the motor in the reverse direction from a rotational position of the motor at the time point at which the rotation of the motor is switched into the reverse direction, based on the detection signal; and a transmitting unit that transmits a stop control signal to the motor driver for stopping an output of the drive signal to the motor , when the movement amount is a predetermined first movement amount or more and a duty ratio of the PWM signal is a predetermined first duty ratio or more. a measurement unit that detects, based on the detection signal, a time point at which a rotation of the motor is, caused by an external factor, switched into a reverse direction that is reverse to a target rotational direction while the speed command signal and the rotational direction signal are being input, and measures, as the movement amount, a movement amount of the motor in the reverse direction from a rotational position of the motor at the time point at which the rotation of the motor is switched into the reverse direction, based on the detection signal; and a transmitting unit that transmits a stop control signal to the motor driver for stopping an output of the drive signal to the motor , when the movement amount is a predetermined first movement amount or more and a duty ratio of the PWM signal is a predetermined first duty ratio or more. <EOS>