With a simple configuration, increase in size can be avoided, usage durability is improved, and occurrence of insufficient electrical connection caused by dust can be prevented well. A crank part is provided in at least one of both contacts including elastic beam-like members. Both of the contacts are provided with cut-away parts, which substantially increase the span lengths of the elastic beam-like members, and gaps between the contacts and an insulating housing which ensure flexibility of the elastic beam-like members to ensure flexibility and prevent permanent deformation of the contacts while enhancing elasticity of the contacts. Dust which has entered the interior thereof is moved along the crank part to ensure electrical conductivity well, which is an employed configuration.