Provided is a wheel bearing with a sensor wherein the detection accuracy does not deteriorate due to change in the environment or long term use, and the load to be applied to a wheel can be estimated accurately. The fixing side member among the outer member and the inner member of a wheel bearing is provided with a sensor unit. The sensor unit consists of a strain generation member, and a sensor (22) which detects the strain. A main load estimation means (31) for estimating the load applied to the wheel by using the average value of the output signal from the sensor (22), and an amplitude processing load estimation means (36) for estimating the load by using the amplitude value of the signal waveform of an output signal from the sensor (22) when a rolling element (5) passes are provided. A drift amount estimation means (37) for estimating the amount of drift of an estimated load output (s1) using the average value of the main load estimation means (31) by the amplitude processing load estimation value (s2) is provided. A correction means (33) for correcting the amount of drift is provided.
