A helical broach 1 for roughing includes a cutting tooth part 30 in which n spline teeth 31 are arranged side by side in an axial direction. The spline teeth 31 each include cutting teeth 32 which are arranged at a predetermined helix angle. The cutting teeth 32 each have an acute angle portion and an obtuse angle portion on both sides thereof in a circumferential direction. The cutting teeth disposed on the first to n−1th spline teeth 31 (S1 to Sn−1) in the circumferential direction are each formed in such a way that its height on the acute angle portion side differs from that on the obtuse angle portion side. The cutting teeth (Sn) of the nth spline tooth (Sn) are each formed in such a way that its height stays constant in the circumferential direction.