PURPOSE: To prevent the occurrence of metallic powder resulting in dielectric breakdown of a coaxial feeder and intend a semipermanent life of a roller type electric contact and the coaxial feeder by performing electric connection between an outer conductor and the other outer conductor and electric contact between an inner conductor and the other inner conductor through the electric contact which is formed of a roller.

CONSTITUTION: The other outer conductor 25 or the other inner conductor 21, having a somewhat smaller or larger dia. than an outer conductor 27 or an inner conductor 25, is arranged so as to be overlapped over the outer conductor 27 or the inner conductor 25 at a preset length in a cross direction, and electric connection between the outer conductor 27 and the other outer conductor 25 and electric contact between the inner conductor 25 and the other inner conductor 21 are performed through an electric contact which contains a roller 55 mounted on the outer periphery or the inner periphery of the inner conductor 21 or the outer conductor 27, respectively. In this way, the electric contact of a coaxial pipe between the fixed side and the moving side is satisfactorily achieved, so that no damages occur due to friction because of the presence of the roller and no dielectric breakdown of the coaxial pipe occurs because of no metallic powder, etc., to improve the operation rate of a high frequency device.