PURPOSE: To prevent generation of electric potential with respect to electromagnetic interference(EMI) by adhering a conductive gasket to an upper edge of a conductive container, and covering the gasket by a conductive lid to form an electrical bridge between the container and the lid.

CONSTITUTION: A form-in-place conductive gasket 1, for example, is formed at the site along an edge which can be fitted to a lid of a substrate 2 to be shielded. An area 13 of a container 12 to which the gasket 11 is fitted has a shoulder 14, and the gasket 11 is formed thereon. Even if the area is free of shoulder 14 but is flat, it has a positioning place of notch, dowel or passage, and the gasket is mounted thereon. The container and the lid are formed of a conductive material, such as a metal, a plastic with metal plating, a metal/ plastic laminate and a composite material. The gasket is formed of an elastomer resin, and the conductivity is given by mixing one or more kinds of conductive fillers in a resin. The gasket can be fitted easily and inexpensively to an arbitrary substrate, in an arbitrary shape.