At least one or more sensor for detecting a load acting on a wheel support bearing apparatus is provided in such bearing device, a signal processor for processing an output signal of those sensors to generate a signal vector and a load calculator for calculating the load, which acts on a vehicle wheel, from the signal vector, are provided. The load calculator has a function of determining the presence or absence of a predetermined state of a vehicle, which may affects a result of calculation of the load, and performing two types of calculation process appropriate to the presence or absence. The presence or absence of the predetermined state of the vehicle, which is determined by the load calculator is, for example, ON/OFF of a brake.