To provide a bearing assembly having a temperature sensor built therein, in which the accuracy of detection of the abnormal temperature is increased, the number of component parts is reduced and the productivity can be increased, a rolling bearing assembly (1) includes a sealing member (7) secured to a stationary bearing ring and a temperature sensor (13) is secured to the sealing member (7). The stationary bearing ring is an inner race (2) if the bearing assembly (1) is of an outer race rotating type. The sealing member (7) is made up of a core metal 9 and an elastic member (10) made of a rubber or resin. The temperature sensor (13) is fixed to the core metal (9) of the sealing member (7) either by means of an insert molding of the elastic member (10) or soldering after forming the sealing member (7). The temperature sensor (13) is in the form of a chip-type laminar thermistor.