Patent ID: 7388478

Claim:
An apparatus comprising: a detecting unit, disposed in an inside of a tire, that is configured to directly detect an inflation pressure of the tire and outputs a detection signal indicating the tire inflation pressure; a deflation time determining unit that is configured to: set a predetermined threshold value lower than a normal inflation pressure of the tire such that the inflation pressure of the tire reaching the predetermined threshold value indicates deflation of the tire; calculate, from the detection signal outputted from the detecting unit, a deflation rate, at which the tire is deflating per unit time, when the inflation pressure detected in the detecting unit is higher than the predetermined threshold value, and determine, from the calculated deflation rate, a specific time, at which the tire inflation pressure becomes lower than the predetermined threshold value when the inflation pressure detected in the detecting unit is higher than the predetermined threshold value, or a specific period of time from a base time to the specific time; and an outputting unit that is configured to output information showing the specific time or information showing the specific period of time.