To provide a single pipe made of aluminum and its clamp that can easily six, even by hand, a single pipe such as a crosspiece or a batter to a form for the placement of ready-mixed concrete in civil engineering or construction work, without using a special fastening tool.

A single pipe 1 is made of aluminum and two cuts are made inside the pipe 1 to form a three-layered aluminum single pipe which appears to consist of three singles pipes aligned and connected together. Holes 2 for clamps are bored in portions of the center pipe of the three pipes, and the aluminum single pipe 1 and the form for placement of ready-mixed concrete are fastened together using the holes 2.