To properly control a brake braking force which becomes antilock operation without causing erroneous operation when normal number of revolutions cannot be recognized by a received sensor signal.

This device detects a rotation speed of a wheel 31 and controls a brake braking force by the detected signal. The rotation speed of the wheel 31 is detected by a power generation type sensor 17. The detected signal of the rotation speed of the sensor 17 is FM-modulated and transmitted as a feeble radio wave from a transmission part 5A of a wireless transmission means 5. A reception part 5B outputs a sensor signal which is a signal of wheel rotation speed and a radio wave intensity signal from the received sensor signal and outputs a signal (ABS signal) in which these signals are overlapped. A controller for controlling a braking force determines the control of a brake braking force in accordance with components of the sensor signal and the radio wave intensity signal from the signal in which they are overlapped.