To enhance a detecting capability for monitoring a bearing assembly and also to minimize complication of the structure resulting from increase in functionality, a vehicle mounted bearing assembly 51 includes inner and outer members 2 and 1 with rows of rolling elements 3 operatively interposed between the inner and outer members 2 and 1, and a rotation detecting sensor 4. A sensor output from the rotation detecting sensor 4 is digitalized by a digitalizing unit 101 and is subsequently transmitted wireless by a transmitting unit 105. One or both of status detecting sensors 52, 53 for detecting different statuses of the bearing assembly 51 other than rotation such as temperature and vibration occurring in the bearing assembly 51 may be additionally employed. A signal coordinating unit 104 may also be used for coordinating the respective sensor outputs from the rotation detecting sensor and the status detecting sensors to enable those sensor outputs to be transmitted wireless by the transmitting unit 105.