Installed in a ball bearing which supports a rotation axis (a supported part) freely rotatable are a control unit, a memory unit wherein specified bearing initial information proper to the ball bearing is stored, and a wireless tag equipped with a radio antenna and a transmission/reception unit which transmit/receive information between this memory unit and the exterior. Then, when the bearing motion information on the motion state of said ball bearing is input to the transmission/reception unit, the control unit has a memory unit which stores the motion information. By this, a bearing, its management system, and its management method wherein an appropriate information management is easy can be provided.