A peeling device for a resin layer coating a rectangular wire in which an outer side of a metal conductor having a rectangular shape in cross section is coated with the resin layer, including a processing blade configured to peel off the resin layer, a jig configured to hold the rectangular wire, and a position detection means configured to detect a position of a cutting edge of the processing blade with respect to a surface of the metal conductor, in which the cutting edge of the processing blade is caused to penetrate into a predetermined thickness position of the resin layer, and the processing blade and the rectangular wire are relatively moved in a longitudinal direction of the rectangular wire without contact of the cutting edge with the metal conductor to perform treatment of peeling off the resin layer.