PURPOSE: To prevent the congestion of a signal line set between a switchboard and a radio base station, and to reduce the load on the switchboard by measuring the radio wave levels of plural peripheral radio base stations via a receiver of a mobile radio terminal, and deciding a radio base station having the highest radio wave level to report it to the switchboard.

CONSTITUTION: The radio wave levels, i.e., the executing conditions are measured for switching channels of a mobile radio exchange system. Then, a radio base station 3 and a peripheral radio base station 4 having the highest radio wave levels are decided. In such a case, the radio wave levels of plural stations 4 are measured by a radio receiver 6 of a mobile radio terminal 5 based on the instruction of a switchboard 1. Then, a radio base station having the highest radio wave level is decided and reported to the switchboard 1. Thus, it is not required to issue the instruction of measurement to plural stations 4. As a result, the congestion is reduced for a signal line set between both stations 3 and 4, therefore, the processing of the switchboard 1 can be reduced.