An image forming apparatus has an image forming device for forming an image on a recording material; a heating member heating the image formed on the recording material in a nip portion; an endless belt conveying the recording material toward the nip portion formed between itself and the heating member; a contacting and separating device for bringing the heating member and the belt into the contact with each other and for separating the heating member and the belt from each other; and a detection device for detecting the temperature of the belt. If the detected temperature of the belt reaches a predetermined temperature, an image formation job is interrupted, and the heating member and the belt are separated.