To provide a positioning jig of a hole for mounting parts for a vehicle capable of markedly reducing a working burden when mounting the parts for the vehicle and remarkably shortening a working time of a mounting work.

By positioning extension parts 3a and 3b in directions of arrows x and z by locking parts 8a and 8b and positioning the extension parts 3a and 3b in the direction of an arrow y of the vehicle by positioning parts 15a and 15b, punching positions of the holes for mounting the parts for the vehicle required when mounting a rear under spoiler can be exactly showed to a rear bumper 17 based on a marking-off mark 14 even if this jig is positioned at the rear bumper 17 by using the locking parts 8a and 8b and the positioning parts 15a and 15b. As a result, the hole for mounting the parts for the vehicle can be formed at an optimum position only by forming a hole at the position of the marking-off mark 14, without performing work for removing the rear bumper 17 by a worker.