The present invention relates to the control of a phase control circuit and, more particularly, to a DPLL circuit used to accomplish synchronization when connecting a digital network connecting unit such as a digital service unit (DSU) with a radio unit such as a personal handy phone system (PHS); it prevents a problem involved in the phase control during sending or receiving. The phase control circuit has: a phase comparator circuit that compares the phase difference between a synchronizing signal and a signal to be controlled and outputs a phase control signal according to a comparison result; a phase changing circuit that changes the phase of the signal to be controlled according to the phase control signal; and a mask circuit that masks the phase control signal supplied to the phase changing circuit according to a phase control disable signal.