The invention provides a structure of a jack in which the quantity of contacts are easily increased. The jack comprise a housing allowing a plug to be inserted therein, the housing comprises a first housing and a second housing in an embedded manner, the first housing comprises a cylindrical first base portion forming a plug inserting hole allowing insertion of the plug and a semi-cylindrical first spring holding portion integrally formed with the first base portion, and the second housing comprises a cylindrical second base portion with an end surface at the opposite side of a surface formingthe plug inserting hole and a semi-cylindrical second spring holding portion integrally formed with the second base portion.