PURPOSE: To attain the prevention of increment of inducel interference and to improve the reliability of a radio equipment by increasing transmission power corresponding to the dropping quantity of reception power at a slave station and saving sending when the transmission power of its own station is abnormally increased.

CONSTITUTION: A reception power detection part 5 connected to a reception part 3 detects reception power to output it to a transmission power control part 7, a differential circuit 6 and a transmission SW control part 9. The control part 7 calculates the rain-fall attenuation of a down line based on reception power information inputted from the detection part 5 to output control voltage to a transmission part 11 so as to increase the transmission power of the same quantity with attenuation. The transmission part 11 increases transmission output based on the voltage. Besides, transmission power detected by the transmission power detection part 8 is fed back to the control part 7 to realize the stabilization of control.