A cavity reentrant cylindrical resonator formed by threading an inner conductor to an outer conductor, wherein an area allowing a screw (2) to deform therein is formed by forming, in a female screw hole inside the inner conductor (1), an internal cavity (5) not threaded with the screw (2) from the seat surface (4) of the inner conductor. Accordingly, the perpendicularity of the screw (2) to the seat surface (4) and the deviation of the perpendicularity of the female screw hole inside the inner conductor (1) can be absorbed by the deformation of the screw (2) to uniformly and securely bring theseat surface (4) of the inner conductor into contact with the bottom face (3a) of the outer conductor (3). As a result, the occurrence of an intermodulation distortion can be suppressed.