PROBLEM TO BE SOLVED: To provide a DC brushless motor, the rotating speed of which can be controlled with high accuracy even when the motor is operated at a low speed without being affected from the uneven magnetization of a rotor magnet and the errors of the mounting positions of Hall elements. SOLUTION: A speed controller controls the rotating speed of a DC brushless motor 1, in such a way that a plurality of Hall elements 2-4 detect the rotational position of the motor 1, and frequency dividing circuits 5-7 obtain rotating speed signals which indicate the rotating speed of the motor 1. Then a reference clock generating circuit 12 generates a reference clock, in accordance with an aimed rotating speed, and error signal generating circuits 8-10 detect the discrepancy of the rotating speed by comparing the rotating speed signals with the reference signal and output error signals. In addition, a signal combining circuit 11 obtains a speed control signal by combining the error signals.
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