To provide a structure and a construction method for interior finishing of a floor and a wall, which enable a wall material to be accurately and easily installed, and which bring about a high degree of freedom of operation steps and excellent constructibility.

In this construction method for the interior finishing of the floor and the wall, wherein a flooring material and a wall material are arranged on the inside of a skeleton of a structure, a floor material 1 by the wall is precedently arranged in the installation place of the wall material 2 which is installed as interior finishing. A general section floor material 3 is installed on a skeleton floor 7c wherein the floor material 1 is not arranged. In this case, a panel-like definitely-shaped member can also be used as the floor material 3.