A heat fixing apparatus, in which a recording material, with an unfixed image passes through a fixing nip formed by a fixing member and a pressurizing member, has an electro-conductive member to be in contact with the recording material disposed downstream of the fixing nip with respect to the recording material conveying direction, wherein a bias voltage is applied to at least one of the fixing member and the electro-conductive member. As recording materials are consecutively fed, the bias voltage applied while the recording materials pass through the fixing nip portion is gradually decreased in accordance with the number of heated recording materials. Thus, smeared image trailing edge upon fixing is prevented from occurring, and the amount of toner adhering to the surface of the fixing member or the surface of the pressurizing member is reduced, so that image errors such as toner contamination are prevented from occurring.