To contrive attachment to an outer wall having unevenness by matching the outer face shape of a part of a support member supporting a down pipe with the inner face shape of a hole drilled in the outer wall of a building.

A metallic down pipe support tool 1 is constituted of a support part 2 supporting a down pipe and a fixing screw 3. The holding part 2 comprises a gutter support part 21 having the half-outer face shape of the down pipe and an equal gutter support face, a reinforcing part 22 welded on the rear face of the bottom part, and a conical leg part 26 welded on the rear face of the bottom part of the reinforcing part 22, and a locking projection part 24 is provided on a both-side part 23. Next, the insertion hole of the screw 3 is provided on the support part 21, the reinforcing part 22 and the leg 26, and the outer shape of the leg 26 is matched to the inner face of the hole provided on the outer wall. The leg 26 is inserted in a truncated conical hole provided on the outer wall during execution, after the screw 3 is screwed on the steel frame of a building through the through hole of the leg 26 from the side of the support part 21, the down pipe is pushed in the support part 2, and a projection part 24 is locked on the groove of the upper and lower directions provided on both the side walls of the down pipe. Thereby even when the outer wall having large unevenness exists on the surface, the down pipe support tool can be vertically attached to the outer wall face.