A radio wave reception converter receives a radio wave and converts the radio wave into an electric signal, and includes a horn introducing a radio wave, and a waveguide arranged at the rear of the horn for guiding a radio wave introduced by the horn. An insulation sheet is located between the waveguide and the horn to seal hermetically the interior of the waveguide and the horn. The connecting part between the waveguide and the horn is covered with an exterior cabinet. The front opening of the horn is covered with a feedome. The structure facilitates the connecting work between the waveguide and the horn, and can ensure airtightness at the connecting part.