TIRE AIR PRESSURE MONITOR DEVICE

A TPMSCU (4) comprises: a rotational position calculation unit (4a) that detects a rotational position for each wheel when a wireless signal including a specific sensor ID has been transmitted; a wheel position determination unit (4c) that acquires the rotational position of each wheel (1) a plurality of times and accumulates the same as rotational position data for each wheel (1), and determines the wheel position corresponding to the rotational position data with the least degree of dispersion among all the rotation position data as the wheel position of a transmitter (2d) corresponding to the sensor ID; and a rotational position detection inhibition unit (4e) that inhibits the detection of the rotational position of each wheel (1) by the rotational position calculation unit (4a) when a braking control that controls a wheel cylinder pressure of the wheels is being executed.