A motor drive controlling apparatus, 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; 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, wherein the motor driver is adapted to control a three-phase motor and provides 120-degree conduction as a conduction method from a start of rotation of the motor to a predetermined rotational speed or provides 180-degree conduction as a conduction method for the predetermined rotational speed or more, and characterized in that the controller has a measurement unit that detects a time point when rotation of the motor is switched to a reverse direction of a target rotational direction that is based on the rotational direction signal by an external factor during input of the speed command signal, based on the detection signal, and measures a movement amount in the reverse direction from a rotational position of the motor at a time point of the switching, based on the detection signal, and a transmitting unit that transmits, to the motor driver , a switching signal that switches a conduction method for the motor driver from the 180-degree conduction to the 120-degree conduction in a case where the movement amount is a predetermined threshold 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; 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, wherein the motor driver is adapted to control a three-phase motor and provides 120-degree conduction as a conduction method from a start of rotation of the motor to a predetermined rotational speed or provides 180-degree conduction as a conduction method for the predetermined rotational speed or more, and characterized in that the controller has a measurement unit that detects a time point when rotation of the motor is switched to a reverse direction of a target rotational direction that is based on the rotational direction signal by an external factor during input of the speed command signal, based on the detection signal, and measures a movement amount in the reverse direction from a rotational position of the motor at a time point of the switching, based on the detection signal, and a transmitting unit that transmits, to the motor driver , a switching signal that switches a conduction method for the motor driver from the 180-degree conduction to the 120-degree conduction in a case where the movement amount is a predetermined threshold or more. a measurement unit that detects a time point when rotation of the motor is switched to a reverse direction of a target rotational direction that is based on the rotational direction signal by an external factor during input of the speed command signal, based on the detection signal, and measures a movement amount in the reverse direction from a rotational position of the motor at a time point of the switching, based on the detection signal, and a transmitting unit that transmits, to the motor driver , a switching signal that switches a conduction method for the motor driver from the 180-degree conduction to the 120-degree conduction in a case where the movement amount is a predetermined threshold or more. <EOS>