PURPOSE: To reduce the number of times of channel switching during talking in an automobile telephone exchange.

CONSTITUTION: The automobile telephone set is configured for a small zone, and this selective system consists of a narrow radio base station 3, a broad band radio base station 4, and the storage section 6 and the discrimination section 7 of an automobile telephone set exchange 5. The narrow radio base station 3 controls each small radio zone 1 and the broad radio base station 4 controls a large radio zone 2 including the small radio zone 1. The discrimination section 7 of the automobile telephone exchange 5 discriminates whether the narrow band radio base station 3 or the broad band radio base station 4 is used for the speech channel of a subscriber based on subscriber information stored in the storage section 6 and allocates the speech channel to a subscriber.