Tire pressure decrease detection apparatus and method, and computer readable medium therefor

A tire pressure decreased detection apparatus comprising rotation speed information detection means, rotation acceleration information calculation means, resonance frequency estimate means for time-series estimating a torsional resonance frequency of the rotation speed information, correlation calculation means for, regarding left and right wheels of driving wheels, calculating a time series correlation of the rotation acceleration information of the left and right wheels, and determination means for determining a decrease in pressure of the tires based on the estimated torsional resonance frequency. In a case where the correlation exceeds a predetermined threshold value, the resonance frequency estimate means stops estimating the torsional resonance frequency.