PURPOSE: To eliminate the need for the adjustment of a free-running frequency by supplying an output of a 2nd phase comparator to a 2nd low pass filter, and synthesizing the output of a 1st low pass filter and the output of a 2nd low pass filter with a prescribed ratio so as to form a control voltage of a voltage controlled oscillator.

CONSTITUTION: A 1st phase comparator 2 compares the phase of a horizontal synchronizing signal with an output of a voltage controlled oscillator 8 and supplies a comparison signal to the 1st low pass filter 4. The 2nd phase comparator 12 compares the phase of an output of a frequency divider circuit 14 with the phase of an output of the voltage controlled oscillator 8 and supplies a comparison signal to the 2nd low pass filter 10. Outputs of the 1st low pass filter 4 and the 2nd low pass filter 10 are synthesized at a prescribed ratio at a synthesis circuit 6 and its combined voltage is applied to the voltage controlled oscillator 8. A stable frequency is outputted from a crystal oscillation circuit 16 and the oscillated frequency is approached to nearly the said frequency. Thus, the adjustment of the free-run frequency is not required.