A hermetically sealing device includes a conductive seal member (2) which is integrated with a conductive member (1) extending into a casing (3) and seals a space between the conductive member (1) and an inserting section for the conductive member (1) on the casing (3). In the conductive member (1), an electromagnetic wave shield layer (11) is laminated on a cover film which protects the surface of a base film having a circuit pattern, an insulating layer (12) is laminated on the electromagnetic wave shield layer (11), the insulating layer (12) has an opening section (12a) such that a part of the flat section of the electromagnetic wave shield layer (11) is exposed, and the seal member (2) is integrated with the conductive member (1) to cover the opening section (12a) and is brought into contact with the electromagnetic wave shield layer (11) through the opening section (12a).