To eliminate slack of a sheet and prevent generation of wrinkles and involving of the sheet into a fixing roller, even in the case of a long-sized output and an output to a continuous web such as continuous paper at high speed.

A driving roller 71 has a rotary shaft 73, a driving means 80 for rotating the rotary shaft 73 in a prescribed direction, and a roll part 74 constituted of cylindrical members of a prescribed number on the rotary shaft 73. A roll part 74a where the center of the sheet 10 passes is formed to have a larger outer diameter than those of roll parts 74b arranged on both sides of the roll part 74a so that the roll part 74a may be brought into contact with the driving roller 71 by prescribed pressing force. The driving means 80 drives the driving roller 71 so that force for pulling the sheet 10 may be constant.