To provide a transmission timing controller controlling a transmission timing of a slot based on newest transmission timing control information.

The controller controls a transmission timing of a transmission slot based on transmission timing control information received from a relay station and is provided with a timer 13 making count operation synchronously with a frame synchronizing signal, a calculation means 11 calculating a timer value corresponding to the transmission timing based on the transmission timing control information, a storage means 14 storing the value calculated by the calculation means, and a comparison means 16 providing an output of a coincidence detection signal when the count of the timer is coincident with a value stored in the storage means 14. Since the calculation means calculates a value going to be counted by the timer, the calculation means utilizes the newest transmission control information obtained the reception slot received after the timer starts counting (after a frame synchronously with is received) for the calculation.