To provide a post easily installable without forming a gap between the wall and the post, enabling the attachment of additional parts to a pipe above the post, provided with a plurality of leg posts having different lengths on the pipe above the post, having high toughness and long service life and effective for shortening the installation work time and getting high economic effect.

The post is composed of an upper pipe 1 and a pair of leg posts 2, 3 having different lengths and integrally attached to the pipe 1. A knocking piece 4 is placed on the upper pipe 1 and knocked from above with a hammer, etc., to uniformly apply the force to the multiple legs. The formation of a gap between the wall and the post by the deformation of the leg is prevented and additional parts are easily attachable to the pipe 1 of the post to reduce the work for the installation of wall panels.