A tire wear amount estimating method for estimating a tire tread wear amount from a radial acceleration of a tire detected using an acceleration sensor, the method comprising the steps of: detecting the radial acceleration of the tire using the acceleration sensor disposed on an inner surface of a tire tread; extracting a radial acceleration waveform of the tire covering a neighborhood of contact patch from the detected radial acceleration; obtaining a differentiated acceleration waveform by differentiating the radial acceleration waveform of the tire; calculating a leading-end differentiated peak value and a trailing-end differentiated peak value, which are magnitudes of peaks appearing at two contact patch ends of the differentiated acceleration waveform, from the differentiated acceleration waveform, characterized in that said method comprises further the steps of: calculating a differentiated peak ratio, which is a ratio between the leading-end differentiated peak value and the trailing-end differentiated peak value, for each of the leading-end differentiated peak values and the trailing-end differentiated peak values obtained by repeating the steps to a plurality of times, and extracting either one of the leading-end differentiated peak values and the trailing-end differentiated peak values, having the differentiated peak ratio within a lower limit range of 0.6 to 0.8 and an upper limit range of 1.0 to 1.2, or computed values computed from the leading-end differentiated peak values and the trailing-end differentiated peak values having the differentiated peak ratio within a lower limit range of 0.6 to 0.8 and an upper limit range of 1.0 to 1.2, as differentiated peak values for wear estimation; calculating a mean differentiated peak value, which is a mean value of the plurality of differentiated peak values for wear estimation extracted in step; and estimating the tire wear amount from the mean differentiated peak value. detecting the radial acceleration of the tire using the acceleration sensor disposed on an inner surface of a tire tread; extracting a radial acceleration waveform of the tire covering a neighborhood of contact patch from the detected radial acceleration; obtaining a differentiated acceleration waveform by differentiating the radial acceleration waveform of the tire; calculating a leading-end differentiated peak value and a trailing-end differentiated peak value, which are magnitudes of peaks appearing at two contact patch ends of the differentiated acceleration waveform, from the differentiated acceleration waveform, characterized in that said method comprises further the steps of: calculating a differentiated peak ratio, which is a ratio between the leading-end differentiated peak value and the trailing-end differentiated peak value, for each of the leading-end differentiated peak values and the trailing-end differentiated peak values obtained by repeating the steps to a plurality of times, and extracting either one of the leading-end differentiated peak values and the trailing-end differentiated peak values, having the differentiated peak ratio within a lower limit range of 0.6 to 0.8 and an upper limit range of 1.0 to 1.2, or computed values computed from the leading-end differentiated peak values and the trailing-end differentiated peak values having the differentiated peak ratio within a lower limit range of 0.6 to 0.8 and an upper limit range of 1.0 to 1.2, as differentiated peak values for wear estimation; calculating a mean differentiated peak value, which is a mean value of the plurality of differentiated peak values for wear estimation extracted in step; and estimating the tire wear amount from the mean differentiated peak value.