To make it possible to reduce, the cost for motors and further, the transient time it takes for a motor to be stabilized, by counting pulses of a deformed frequency signal and thereby creating absolute angle positions.

A deformed frequency signal FG is input[ to the period detecting section 41 of a frequency deformation point detecting section 40, and is further inpoutted ro the clock terminal on an absolute angle generatar 45. A frequency detector 41 detects the period of the input frequency signal FG, and outputs it to a comparator 44 and a delay unit 42. The delay unit 42 delays the period output from the period detector 41 by one period of the input frequency signal FG, and outputs it. A gain adjuster 43 is fed with a period previously detected from the delay unit 42, and, after gain adjustment, outputs it to the comparator 44. The absolute angle generator 45 is reset each time a frequency deformation point is detected through the comparator 44 of the frequency deformation point detecting section 40. The absolute anglegenerator 45 counts the number of pulses of deformed frequency signal generated by the rotation of a motor, and calculates an absolute angle position.