PURPOSE: To stabilize one of two voltage-controlled oscillator by supplying the control input of the phase leading-in circuit of one voltage-controlled oscillating circuit to the other voltage controllng oscillator as a control bias signal.

CONSTITUTION: A voltage-controlled oscillator VCO1 constitute a phase leading- in circuit by a frequency divider 11, a phase detector 12, and an LPF13. The output frequency of the oscillator VCO1 is in proportion to the multiple value of a supply signal to terminals CNT1 and CNT2. A phase difference between a timing singal from an input IN and the output of a voltage-controlled oscillator VCO2 is applied to an oscillator VCO2 through a phase detector 21 and an LPF22. When the oscillators VCO1 and VCO2 are formed on the same semiconductor chip, they have the same power voltage and temperature characteristics, and the oscillator VCO2 is not under the influence of variation in power source and fluctuations of temperature.