A fixing device includes a cylindrical belt, a nip portion forming member contacting the belt, a halogen heater including a bulb filled with gas and having a sealing portion sealing the bulb, a filament inside the bulb and having a light emission portion, an external lead extending to outside the halogen heater, and a metal body arranged in the sealing portion and electrically connected the filament and the external lead, and a reflection member reflecting the radiation light of the halogen heater toward the nip portion forming member, the reflection member being long in a longitudinal direction of the halogen heater, wherein a longitudinal end of the reflection member is configured to lie in an area between an end of a light emission area constituted by the light emission portion of the halogen heater and the metal body in the longitudinal direction of the halogen heater.