A motor drive controlling apparatus includes: a controller that outputs a drive control signal; a motor driver that generates and outputs a drive signal to a motor; and an encoder that detects a rotational position of the motor. 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 by an external factor during input of the speed command signal, and measures a movement amount in the reverse direction from a rotational position of the motor at a time point of the switching, and a transmitting unit that transmits, to the motor driver, a switching signal that switches a conduction method from 180-degree conduction to 120-degree conduction in a case where the movement amount is a predetermined threshold or more.