A core cutter includes a tubular body portion and a plurality of cutting blades arranged at a tip end of the body portion at predetermined intervals in a circumferential direction. At least one cutting blade serves as an inner cutting blade, and the remaining cutting blades serve as outer cutting blades. Through grooves penetrate a tip end of the body portion to open toward a tip end side of the core cutter. Each of the cutting blades having the same circumferential-direction size as the through groove. Gullets are configured to discharge the chips, each of the gullets formed by an outer peripheral surface. The cutting blades are welded to through grooves such that a radially inner end of an axial-direction tip end portion of each of the cutting blades coincides with or substantially coincides with a peripheral surface of an axial-direction tip end portion of the gullet.