A control device for an automatic transmission includes a current detecting unit for detecting motor current. The current detecting unit has a counter for counting variation number of a rotational position signal output from a rotational position detecting unit for detecting the rotational position of a motor, and an electrical angle 180° judging unit for judging rotation of electrical angle 180° of the motor. A voltage occurring in a current detecting resistor is sampled at a timing of each integral multiple of the electrical angle of 180° judged in the electrical angle 180° judging unit, and rotation of the motor is controlled in accordance with the difference between motor target current calculated in the motor target current calculating unit and motor current.