The logical channels are made to include a logical channel for control and a logical channel for data transmission, the radio physical channel are made to be commonly used for a plurality of logical channels, and one logical channel is made to have a correspondence relationship with one radio physical channel, and the channel assignment apparatus includes: traffic monitoring detection means that detects occurrence of traffic of the logical channels; and logical channel assignment means that, according to occurrence of the traffic of the logical channels, sequentially assigns required resources on the radio physical channel to the logical channels, so that the object is achieved.