Abstract: An apparatus for inspecting a side wall of a tire including an optical sensor provided so as to face a side wall surface of a rotatable tire for reading a variation of distance to the side wall surface as an irregularity signal, memory means for storing an irregularity signal read by the optical sensor, usable data discrimination means for discriminating whether or not the signal read out from the memory means is usable as irregularity inspection data, correction means for removing detection-unrequired irregularities from the data discriminated as usable data by the usable data discrimination means, height calculation means for finding out an irregularity falling within a predetermined condition in the corrected data and calculating the height of the irregularity, and determination means for determining based on the height of the irregularity calculated by the height calculated means where there is an abnormal irregularity.