PURPOSE: To make possible the data transmisstion even when the reception field is fluctuating and thus to enhance the reliability for the mobile radio system by providing the local allotment time counting function to the mobile station.

CONSTITUTION: When one of plural units of start pulses added with the sequential number given from the base station is received in a correct way, counter 15 is started. And the allotment time of the own station is counted based on the sequential number to carry out the data transmission within the allotted time. In case the next start signal cannot be received from the base station, the data is transmitted repetitivery with every system cycle time from the data tranmsission time based on the counting of the system cycle time via system timer 17. After this, counter 15 and timer 17 are reset when the start pulse is received correctly. Thus, the local allotment time is counted again.