A fixing device includes an endless belt or a fixing belt; a pressure member to contact an outer circumferential surface of the fixing belt; a nip forming member disposed at an interior side of the fixing belt and contacting the pressure member via the fixing belt; a heat source disposed at an interior side of the fixing belt to heat the fixing belt with radiant heat, a plurality of shielding members disposed between the heat source and the fixing belt and movable between a shielding position where the shielding member shields a non-sheet passing area on the fixing belt from the radiant heat from the heat source and a retracted position; and a controller to move the plurality of shielding members between the shielding position and the retracted position at a predetermined time.