For the purpose, a physical quantity regarding a bearing body is detected by a detection sensor provided in the bearing body, and detection information of the detection sensor is transmitted by a wireless transmitting unit provided in the bearing body via wireless communication. At this time, the detection information is transmitted at a first transmission interval when the detection information is smaller than a threshold value and is a normal value, and the detection information is transmitted at a second transmission interval that is shorter than the first transmission interval when the detection information is the threshold value or larger and is an abnormal value.