PURPOSE: To obtain a circuit which generates an encoding signal from a commutation sensor signal to achieve higher reliability and reduction in cost in a three-phase brushless motor with a commutation sensor.

CONSTITUTION: A pulse is generated from a commutation sensor signal with an edge direction judging circuit 11 to be distributed into six. Rotational direction information is obtained with a rotational direction judging circuit 12 with respect to the respective pulses and the pulses are distributed in terms of the direction of rotation with a direction signal output circuit 13. Finally, the results are outputted as encoder pulses from a feedback pulse output circuit 16. Thus, a pulse having the rotational direction information is generated from the commutation sensor signal with the circuit thereby producing an encoder signal.