By performing rough adjustment of a local oscillation frequency by a first lock loop using an up/down counter (5) and micro adjustment of the local oscillation frequency by a second lock loop using an S/H circuit (11), it is possible to eliminate the need of operation of charging and pumping a capacitor according to a phase difference and to omit an LPF using a large-scale capacitor from the frequency synthesizer. Moreover, by performing micro adjustment using the S/H circuit (11), it is possible to accurately lock the local oscillation frequency and eliminate the need of increasing the bit quantity of the up/down counter (5) to increase the control accuracy of the frequency to be locked. Thus, it is possible to rapidly lock the local oscillation frequency to a desired frequency.