A fixing device includes a fixing belt, a pressuring member, a nip forming member, a supporting member, a heating source, a heat conducting member, and a reflecting member. The pressuring member comes into pressure contact with the fixing belt to form a fixing nip. The nip forming member presses the fixing belt toward the pressuring member. The heat conducting member comes into contact with an inner circumference face of the fixing belt and absorbs a radiant heat emitted from the heating source. The reflecting member includes a reflecting part and a regulating part. The reflecting part reflects the radiant heat emitted to the supporting member toward the heat conducting member. The regulating part is unified with the reflecting part and comes into contact with the inner circumference face of the fixing belt to regulate looseness of the fixing belt.