Disclosed is a cast pin equipped with circular grooves which are provided at any location. The cast pin (10) is equipped with: an outer tube (11) in the shape of a hollow body the tip of which is closed; an inner tube (20) inserted into the outer tube (11); and a cooling medium pipe (30) that is inserted into the inner tube (20) and supplies a cooling medium to the interior of the inner tube (20). Three circular grooves (22) are formed at prescribed intervals in the longitudinal direction, for example, on the outer circumferential surface (21) of the inner tube (20). The circular grooves (22) are formed in the outer circumferential surface (21) by applying a cutting tool from the radial outward direction of the inner tube (20).