This repair device includes a casing, a slide shaft slidably arranged with respect to the casing, a turn table rotatably arranged with respect to the slide shaft, and a cutting mechanism installed on the turn table and including cutting tools. The turn table is rotationally displaced while the slide shaft slides in an axial direction, so that the cutting tools helically turn to cut an inner periphery of a nozzle. The cutting mechanism includes a cutting-tool switching unit that switches the cutting tools.