PURPOSE:To speed up the response speed, by providing the phase adjuster taking the phase control signal as control input and adjusting the phase of the output of the voltage controlled oscillator by the amount corresponding to the amount of the phase change of the phase shifter output and changing the phase of the oscillator with the change to the phase shifter. CONSTITUTION:In the PLL system providing the phase shifter 1, phase comparator 2, LPF 3, voltage controlled oscillator VCO 4 and frequency divider 5, inputting the output of the phase shifter 1 to the comparator 2 and changing the phase of the output of the phase shifter 1 by adding the phase control signal VSx to the phase shifter 1, the phase adjuster 6 taking this control signal Vsx(=1, 2) as input signal and adjusting the phase of the oscillated output of VCO 4 by the amount corresponding to the amount of phase of the output of the phase shifter 1, is provided. Further, VCO4 is constituted with the capacitor relaxation oscillator, the charge of given amount to the capacitor is adjusted with the adjuster 6 and the oscillated phase of VCO 4 is adjusted, and the response of the output signal to the phase shift signal is improved independently of the time constant of LPF.