A motor drive controlling apparatus includes: a controller that generates and outputs a drive control signal, in response to input of a speed command signal and a rotational direction signal； a motor driver that generates and outputs a drive signal to a motor, in response to the drive control signal； and an encoder that detects a rotational position of the motor to output an encoder signal. The controller includes: a measurement unit that detects, based on the encoder signal, a time at which a rotational state of the motor becomes, caused by an external factor, different from that commanded by the speed command and rotational direction signals, and measures a movement amount from the time； and a transmitting unit that transmits, to the motor driver, a signal for stopping an output of the drive signal, when the movement amount and a drive-control-signal outputting state satisfy a predetermined condition.
