A wheel bearing assembly for an automotive wheel equipped with a detector for the number of revolutions of a wheel hub. It has an outer member and two inner members mounted in the outer member through rolling elements. A pulse ring in the form of a multipolar magnet is mounted in the bearing assembly so as to be fixedly held in annular grooves formed in the outer periphery of the inner members at their abutting ends or to be supported on one of the inner members. A sensor including a Hall IC is mounted in the outer member at such a position as to face the pulse ring. The pulse ring rotates with the inner members to allow the sensor to detect the rotational speed of the wheel.