To cut down the cost of electric equipment in exterior structure simple and having excellent airtightness by bending the joint part of a cylindrical case and a cover to wrap up the and then covering the junction part of the cover and a connector a sealing resin.

A cover formed of a galvanized sheet iron is fitted to a connector 2 packaged on a circuit substrate so as to cover the main body with a cylindrical case 3. Next, the edge part of the cover 4 is bent to wrap up the joint part with the cylindrical case 3. At this time, in order to facilitate the bending step, a curvature is given to the joint part of the cylindrical case 3 and the cover 4, furthermore, an adhesive is applied to the bent part of the cylindrical case 3 and the cover 4. Finally, in order to fill up the gap between the cover 4 and the connector 2, a sealing resin 5 is poured into the gap to be set therein. Through these procedures, no screws are required at all as well as neither a sealing packing nor an adhesive is required in compliance with the requirements for the airtightness performance, thereby enabling the part numbers to be cut down.