A wear state detection device includes an element configured to generate voltage based on deformation of a tread portion during tire rotation, a voltage detection unit configured to detect the voltage generated by the element, a speed detection unit configured to detect vehicle speed or tire rotation speed, a storage area configured to store waveform data over time of the voltage detected by the voltage detection unit together with the vehicle speed or the tire rotation speed detected by the speed detection unit, a calculation unit configured to calculate frequency of exceedance of a predetermined threshold value based on the waveform data in a predetermined speed range and a predetermined time period stored in the storage area, and a determination unit configured to determine a progress condition of wear of the tread portion based on the frequency of exceedance of the predetermined threshold value calculated by the calculation unit.