The silicon wires formed around metal particles by crystal growth have the problem of metal pollution. For its solution, in the present invention, a silicon bridge is formed through standard silicon processes such as the lithography and the wet etching using hydrofluoric acid performed to an SOI substrate. Thereafter, a thermal oxide film is desirably formed at a high temperature to form a high-quality gate insulating film. It is also desirable to form a coaxial gate electrode. Then, after burying the bridge sections of the silicon bridge in a resist film, the silicon on the bridge girders is removed, and thereafter, the silicon wires buried in the resist film are collected. In this manner, the silicon wires can be collected without dispersing into the hydrofluoric acid solution. Then, a transistor using the silicon wires as a channel is formed.