Wheel bearing has sensor for measuring rotational or angular movements of a wheel with wheel bearing flange and roller bearing attached thereto. The control system includes: a rotational rate sensor having a resonating mass and a controller electrically connected to the rotational rate sensor. The gold eye candidate detecting section detects a gold eye, which is an area of a color included in a color range of a predetermined gold color that is not overlapped with a color range of the predetermined red color, from image by using the detecting threshold value. A recess wall surface on one side of the removal-preventing recess is formed as an inclined surface for guiding the tip end portion of the removal-preventing member in a wedging direction into the removal-preventing recess. A screw cap locks the wheel on the axle.