To solve the problem caused by the fact that the transmission level of a mobile machine becomes inadequate when the mobile machine possibly misunderstands an indication for transmission level variation received from a base station in case of inferior communication quality of a down link and a communication is discontinued as interference with up links to other mobile machine increase at the base station if the transmission level increases by mistake or as the communication quality of the up link to the base station deteriorates if the transmission level decreases by mistake.

The mobile machine which controls transmission power on receiving a transmission power control command sent from the base station by the downlink so that the reception state of the up link to the base station is fixed has a reception quality estimation part 12 which estimates the reception quality of the control command and a transmission power control part 13 which varies the control width of the transmission power according to the estimated quality. Consequently, the problem that the communication state of the down link becomes worse and the transmission power of the mobile machine varies large differently from the indication of the base station is solved.