PURPOSE: To reduce the cost of the communication network and to improve the expansion performance by generating a frame phase so as to be synchronized with a frame phase of other base station in each of plural base stations so as to attain network synchronization without need for a synchronizing signal private line between the base stations.

CONSTITUTION: Upon the receipt of a signal from other base station, a reception circuit 1 extracts a frame phase from a reception signal and gives it to a frame clock generating section 44. Then the frame clock whose frame phase of a relevant base station is in matching with a frame phase of other base station is generated and sent to the reception circuit 1. Then a timing control circuit 4 monitors intermittently the reception circuit according to the timer operation when the base station is not busy. Moreover, a frame frequency is obtained from a reference clock based on a time output of a standard radio wave receiver 5 or a commercial power supply frequency. Thus, the network synchronizing signal is obtained without need of network synchronization exclusive communication line installation between the base stations, the cost is reduced and the system is expanded.