A heating device includes a housing, a heating member, a pressure member, a pair of openings, and a thermal insulator. The heating member and the pressure member extend along a longitudinal direction and press each other to form a nip portion in the housing. The heating member transfers heat to a recording medium passing through the nip portion. The pair of openings is disposed in the housing and opens facing both end portions in the longitudinal direction of the heating member so that air passes through the pair of openings. The thermal insulator is disposed inside the housing between the pair of openings and faces an outer peripheral surface of the heating member.