PURPOSE: To enhance the resolution of pulse in the detection of rotation while allowing decision of the rotational direction through a simple structure.

CONSTITUTION: When the armature 26 of a motor 14 rotates, a pulse is generated from each Hall IC 40, 42 fixed oppositely to a magnet 38 on the armature 26. Two Hall ICs 40, 42 are arranged at an angular interval of 90° and the pulses generated therefrom have a phase difference of a quarter of period. Consequently, the number of pulses per single revolution of the armature 26 is doubled as compared with a case employing a single Hall IC. Furthermore, rotational direction of the armature 26 can be decided by detecting the generation order of pulses from the Hall ICs 40, 42 which is reversed when the rotational direction of the armature 26 is reversed. In the case of a jam protection power window, the count (n) of pulses entering into a dead band can be increased to ensure normal closure of window glass even upon occurrence of lock current and thereby the dead band is halved as compared with the case employing only one Hall IC. This structure positively prevents even a small foreign matter from being caught.