To provide a roller unit which prevents a spiral wire material inserted into a hollow cylindrical roller from moving in the longitudinal direction.

One end 60a of a coil spring 60 is inserted and fixed to a hole 94a of a fixing plate 94 and a protruding part 92 of a cap member 90 is fitted to a recessed part 52b of a fixing roller pipe 52 to fasten the cap member 90 to the fixing roller pipe 52 as well as to fasten the coil spring 60 to the fixing roller pipe 52. This makes the coil spring 60 and the fixing roller pipe 52 into one body. As the coil spring 60 and the fixing roller pipe 52 rotate as one body, the coil spring 60 is prevented from moving in one direction (resulting uneven distribution) depending on the winding direction of the spiral of the coil (in one of the longitudinal directions of the fixing roller pipe 52).