To obtain a waveguide capable of improving reliability and reducing a loss and flexible in an axial direction.

An inner connection part 120 and a corrugate waveguide 12 fixed thereto are movable (slidable) in a lateral direction in Fig.1 inside of an outer cylindrical part 112. Between an outer connection part 110 and the inner connection part 120, a connection part inside space 130 is formed while being connected with a clearance between a right-side end face of an inner waveguide part 111 and a left-side end face of an inner waveguide part 121. An electromagnetic wave leaked from the clearance between the right-side end face of the inner waveguide part 111 and the left-side end face of the inner waveguide part 121 is leaked into the connection part inside space 130. An absorber 140 which absorbs an electromagnetic wave is formed on an inner surface of the outer connection part 110 and on a left-side end face of the inner connection part 120 constituting the connection part inside space 130.