PURPOSE: To reduce power consumption by monitoring the quanlity of speaking and controlling a transmission output in respect to a transmission output control device in a base station or a mobile station on a bidirectional mobile communication network for a digital cordless telephone or the like.

CONSTITUTION: A frame error rate measuring part 7 measures a frame error rate from a radio frame unique word or a CRC check result. When the frame error rate is less than a reference value, a transmission power judging part 8 judges that the transmission power of the base station is excess and the power of a transmission wave outputted from a transmission power amplifying part 9 is reduced.