A processing device processes a frame-shaped workpiece which extends in a prescribed extension direction, and includes, integrally, a plate-shaped web surface portion, a plate-shaped first flange portion that bends and extends from one end of the web surface portion, and a plate-shaped second flange portion which bends from the other end of the web surface portion and extends in the opposite direction to the first flange portion. The processing device includes a shaping device which conveys the workpiece in the extension direction, and an exit side pinch roll device provided further downstream, in the workpiece conveying flow direction, than the shaping device. The exit side pinch roll device includes a first roll which presses a central region of an upper surface side of the web surface portion, and a second roll which presses a central region of a lower surface side of the web surface portion.