at a high level as set forth above the voltage appearing at the input terminal p1 of the microcomputer may be changed from a high level to a low level owing to the manual door opening motion and maintained at a high level owing to the manual door closing motion basically the door movement detection circuit 2 connected to the terminal t2 functions in the same manner as the detection circuit 2 connected to the terminal t1 that is in case of the detection circuit 2 connected between the terminal t2 and the input terminal p2 the voltage appearing in the input terminal p2 may be changed from a high level to a low level owing to the manual door closing motion and maintained at a high level owing to the manual door opening motion in other words the door controller of the embodiment drives the direct current motor when satisfying a specified condition wherein the magnitude of electromotive force induced in the motor winding owing to the manual door opening motion or the manual door closing motion exceeds a predetermined threshold so as to optimally and timely power move the sliding door depending on the manual door movement direction as may be appreciated in the embodied controller the magnitude of the emf can be detected in the form of the potential.