PURPOSE: To hold the balance of a use rate of a communication channel by constituting the device so that an allocation rate of a call in the case of allocating the call to each communication channel can be changed dynamically in accordance with a state of traffic of the communication channel.

CONSTITUTION: A use rate comparing device 221 monitors the difference of use rates of communication channels and in the case its difference becomes a prescribed reference value or above, a switching device 227 is switched and set to an adjustment phase of an allocation rate, a channel is selected by an output of a channel use rate comparing device 223, and a corrected allocation rate is stored in an allocation rate storage area 225. Subsequently, in the case the difference of the use rates becomes the prescribed reference value or below, and the device is switched to a fixed allocation phase, the allocation rate obtained by considering an information transfer delay D is calculated by a channel use rate calculating device 222 and a new allocation rate is stored in the allocation rate storage area 225, and the channel is allocated so as to select the channel by the allocation rate stored in this allocation rate storage area 225.