To provide a mounting tool alleviating labor of mounting a fixing member of a repair component of a building to an existing fixing member of an existing external facing material and allowing simple execution of mounting work of the fixing member.

When a new external facing material 2 is mounted on an outdoor side face of the existing external facing material 1 by the fixing member 3, the mounting tool B is used for mounting the fixing member 3 on the outdoor side face of the existing external facing material 1 by inserting the existing fixing member 5 protruding on the outdoor side face of the existing external facing material 1 in a mounting hole 6 formed in the fixing member 3. The tool includes a hammered section 31 hit by a hammer 30 and a pressing section 32. The hammered section 31 is arranged above the fixing member 3. By impact to the hammered section 31, the fixing member 3 in the state of keeping a bottom-end opening of a vertically-elongated slot hole 6 aligned with the existing fixing member 5 is disposed in a pressable manner with the pressing section 32.