A heating apparatus according to the present invention has a heating portion 102 for conveying a printing plate 120 incorporating a metal support plate, on which a photosensitive layer is formed, into a hot atmosphere radiated from a heat source; upstream conveying rollers and downstream conveying rollers 10, which are disposed upstream and downstream of the heating portion and are structured to hold the printing plate 120 from upper positions and lower positions to convey the support member. In the heating apparatus, at least one of the rollers, which constitute the downstream conveying rollers, has a drive shaft 11 and a central hole through which the drive shaft is inserted. The heating apparatus further incorporates a plurality of disc-like members 12 rotatively joined to the drive shaft and friction members for exerting frictional resistance on the disc-like members which are rotated with respect to the drive shaft are provided. The disc-like members 12 are structured to prevent occurrence of deformation of the printing plate due to expansion or permit passage without crushing of the deformed portion formed due to the expansion.