PROBLEM TO BE SOLVED: To eliminate influence from an outside temperature, and to automaticaly determine leak of a pneumatic tire.
SOLUTION: This leak inspecting device is composed of a CPU 11, a RAM 12, a ROM 13, an input and output part 14, a setter 15, a printer 16 and a display 17. Tire internal pressure of an inspected tire and an outside temperature input through the input and output part 14 are stored in a measured data storing part 121. A reference data is stored in a reference data storing part 123. The CPU 11 corrects the outside temperature corresponding to the internal pressure of the inspected tire to be specified, with a prescribed delay time, and the corrected data is stored in a corrected data storing part 122. The CPU 11 compares the data stored in the corrected data storing part 122 with the reference data stored in the reference data storing part 123, to determine the presence of the leak in the inspected tire, based on a result compared therein. The comparison hereinbefore is carried out using a linear functional approximate expression of varying curves of the tire internal pressure and the outside temperature.