Abstract: The present invention discloses a fixation structure for a blade body of a planing cutter, wherein the planing cutter comprises a cutter body, a blade body, and a plurality of screw connectors. The cutter body is provided on its outer peripheral surface with a cutter seat used for mounting the blade body on which a blade of hard alloy is welded, a cooperating and positioning structure is provided between the joint surfaces of the blade body and the cutter seat, and the blade body is directly threadedly connected on the mounting seat of the cutter body through a plurality of screw connectors. Such fixation structure is simple and the replacement of the blade body is convenient, and is adapted for flat planing cutters and spiral planing cutters.