To provide the bevel machining method and bevel machining device that performs bevel machining and scallop machining of H-shaped steel through batch processing in a short period of time and in the manner in which the wear of a cutter is curbed to the minimum, without being affected by the protrusion size L.

From the flange end portion and web end portion of H-shaped steel W, an L-shaped portion is cut out with the first circular saw edge C1 and the second circular saw edge C2, and the cut-out section 16 is subject to scallop machining by means of a scallop cutter and subsequently to bevel machining through the use of a bevel cutter. Based on this arrangement, the final shape in which the central portion of the web protrudes from the flange end portions in a fixed projection size is effectively formed.