To solve the problem that in addition to ordinary construction work, reinforcement work is needed on the building skeleton side since load of a person is applied to a handrail and in addition to the strength of the handrail itself, the strength of the building skeleton side to which the handrail is fixed should be increased, generally a plywood is partially buried instead of plaster board in the wall to take a reinforcement measure, always additional work is needed, and in some case, reinforcement work is forgotten, so that the wall needs reconstruction.

A base board positioned in the lower part of the wall in the interior of the building is installed as a support for the peripheral devices in the interior of the building.