A tire state detection device that includes: a temperature sensor that detects a temperature in a tire air chamber; an acceleration sensor that detects acceleration associated with rotation of a tire; a pressure sensor that detects pressure in the tire air chamber; a storage unit that stores a plurality of maps for calculating a fatigue state of the tire on the basis of the detected temperature, the detected acceleration and the detected pressure; and a tire fatigue index calculation unit that calculates, by referring to each of the plurality of maps, a tire fatigue index from the detected acceleration, the detected temperature, and the detected pressure.