To provide a roller hemming device, wherein the positioning member can be miniaturized and the layout of members such as a roller is not restricted by the positioning member.

The roller hemming device 10 is provided with a positioning pin 13 which is provided on a workpiece placing member 12 so as to be freely projected or recessed and allows a workpiece 11 to be positioned in the working position by arranging in the projected state to the workpiece-placing member 12 and a pin moving part 14 which is offset to a side near the center 11a of the workpiece 11 by the dimension of S to the positioning pin 13, also provided on the back side of the workpiece-placing member 12 so as to move the positioning pin 13 in a projected or recessed state.