To provide a method for boring a wiring hole and a support for boring in which the center position of a wiring box Q arranged on an inside position of an interior plate P can be easily ensured from outside the interior plate P and the wiring hole P1 can be bored.

The method for boring the wiring hole includes a step for fixing the support 1 for boring at the center of the wiring box Q in mounting the interior plate P, a step for pressing and installing the interior plate P so that the interior plate P can be pierced by a sharp boring part 21 provided on the end of a projection body 20 in installing the interior plate P, a step for inserting a tip of a rotary shaft R1 of a hole saw R at the end of the projection body 20 projecting outside the interior plate P into inside the projection body 20 to support the rotary shaft R1, and a step for boring the wiring hole P1 in the interior plate P with the hole saw R supported by the projection body 20.