Apparatus for fixing a toner image on a toner image supporting member in an electrophotographic copying machine is disclosed. The fixing apparatus comprises three rotary rollers which are in contact with each other under the action of pressing means. One of the three rollers has a smaller diameter than the remaining two rollers. In order to press the toner image supporting member uniformly between the two rollers with which the supporting member comes into contact, the two rollers are disposed in such a manner that the roller axes cross one another.