A fixing device includes a fixing belt, a pressuring member, a pressing member, a shape restricting member and an elastic body. The fixing belt is configured to be rotatable. The pressuring member is configured to be rotatable and to come into pressure contact with the fixing belt so as to form a fixing nip. The pressing member is configured to press the fixing belt to a side of the pressuring member. The shape restricting member is configured to restrict a shape of the fixing belt and having an arc-shaped insertion part to be inserted into an end part of the fixing belt. The elastic body is attached to an end part in a circumferential direction of the insertion part.