This invention there provides a detergent for cleaning tire wheels, which is applied in a foamy state onto the tire wheels, thereby allowing a grime adhered to the surface of the tire wheels to come off from the tire wheels, which contains a surfactant, at least one alkali compound selected from the group consisting of ammonia and amino group-containing alkali compounds, and a color change indicator capable of changing its own color when transferred from an alkaline condition to a neutral condition, in which the alkali compound is contained in the detergent in such an amount that the compound is eliminated from the detergent by reaction with carbon dioxide for the same period of time as required to release most amounts of grime from the surface of tire wheels, and a method of cleaning tire wheels with the detergent.