A guide pin piercing jig includes a curved frame, a front cylinder unit provided at a front end of the frame, and a rear cylinder unit provided at a rear end of the frame, in which the front cylinder unit has a positioning projection and a boring aiming portion at a tip thereof, the rear cylinder unit has a plurality of parallel guide pin insertion cylinders into which to insert the guide pins and a tentative fixing unit provided at a tip of the rear cylinder unit, and the rear cylinder unit is provided at a rear end of the frame slidably so as be directed to a tip of the front cylinder unit. It becomes possible to aim at a proper portion of a living body bone through which to bore a bone tunnel and to pierce the living body bone with guide pins for hollow drills from behind the living body bone to the proper aiming portion in a proper direction.
