WHEEL STATE ACQUIRING DEVICE

PROBLEM TO BE SOLVED: To reduce power consumption by making a battery of a wheel-side device last long. SOLUTION: Air pressure of a tire is estimated based on a wheel speed by a second information processing section 62. Required information is transmitted to wheel-side devices 10-16 when the air pressure of the tire is suspected to be abnormal based on the estimated air pressure value. When the required information is received by the wheel-side devices 10-16, a pneumatic sensor 32 and a wheel information producing/transmitting section 40 are started to provide a power consumption state. The air pressure value of the tire is detected by the pneumatic sensor 32, and wheel information including the air pressure value is transmitted. In the wheel-side devices 10-16, the pneumatic sensor 32 and the wheel information producing/transmitting section 40 or the like are started if necessary, and power is consumed, so that power consumption speed of the battery is decreased and the battery can be made to endure. COPYRIGHT: (C)2005,JPO&NCIPI