Abstract: An MCA radio data communication system linking a base station and a plurality of terminal stations by radio channels through a control station, wherein note is taken of the facts that one radio channel can be occupied for only a certain occupied time T and that even after the completion of one data communication the radio channel is held for within a certain holding time t (T>t). The present invention allows each of a plurality of terminal stations to share the same radio channels without a channel assignment operation. A communication end signal is simultaneously broadcast upon completion of a first data communication and so that another terminal station demanding a second data communication starts its data communication promptly upon receiving the communication end signal without a channel assignment operation.