A fixing device includes a fixing belt, a pressure rotating body, a nip member, a supporting member, a heating source, a heat conducting member and a reflecting member. The pressure rotating body is rotatably arranged outside the fixing belt to come into pressure contact with the fixing belt to form a fixing nip. The nip member is arranged inside the fixing belt to press the fixing belt toward the pressure rotating body. The supporting member supports the nip member. The heating source is arranged inside the fixing belt to emit radiant heat. The heat conducting member is supported by the supporting member in a cantilevered state to come into contact with an inner circumference face of the fixing belt and to absorb the radiant heat. The reflecting member reflects the radiant heat toward the heat conducting member and at least partially comes into contact with the heat conducting member.