To improve deformation resistivity against an outer force, and to improve reliability by suppressing the degradation of characteristics by providing a structure in which the outer side of a waveguide having irregular waveform-shaped wall faces in the longitudinal direction whose cross-section is shaped so as to be rectangular is covered with an outer sheath.

The wall faces of a hollow waveguide 1 whose cross-section is rectangular are formed like an irregular waveform shape in the longitudinal direction, and radio leakage slits 3 are arranged in prescribed intervals in the longitudinal direction at the central positions of the projecting side walls on the short sides of the rectangular shape as necessary. Dielectric tapes for closing the openings of the slits 3 are laminated on the surface of the waveguide 1, and a lubricant such as glue is packed between the waveguide and the outer sheath. Thus, the cross-section is shaped so as to be rectangular so that resistance against any charge deformation due to an outer force can be increased to reduce any deformation, and the degradation of radio propagating characteristics due to the deformation of the waveguide can be reduced, and the fluctuation of the radio leakage amounts or the directivity of radiation can be prevented. Also, the tape is adhered so that the intrusion of any foreign matter can be prevented, and an inter-waveguide partial space can be maintained with an ideal air dielectric constant, and electric characteristics can be improved.