Square end mill

A square end mill comprising;

• a cutting edge portion that includes an end cutting edge and a peripheral cutting edge disposed on a tip side in an axial direction of a tool body, the end cutting edge being disposed from a center side to an outer peripheral side in a radial direction, the peripheral cutting edge being continuous with the end cutting edge, wherein
• the end cutting edge includes at least one long end cutting edge and at least two short end cutting edges, the long end cutting edge is continuously disposed from an end portion on the outer peripheral side in the radial direction to closer to a center in the radial direction when the cutting edge portion is viewed from an end face side in an axial direction, and the short end cutting edges are continuously disposed from other end portions on the outer peripheral side in the radial direction to middles on the center side in the radial direction when the cutting edge portion is viewed from the end face side in the axial direction, and
• the short end cutting edges each include a first gash on a region from a line connecting the end portion on the center side in the radial direction to a proximity of the center in the radial direction to each of the long end cutting edges on rear sides in the rotation direction, the first gash has a rear side in the rotation direction and a front side in the rotation direction where a second gash and a third gash are formed respectively, and the first gash, the second gash, and the third gash are formed in curved surface shapes depressed to a shank side on an opposite side in the axial direction of the cutting edge portion when the cutting edge portion is viewed from the end face side in the axial direction.