A connector and a metal case for a counterpart device, the connector comprising: a terminal metal fitting that is physically and electrically connected to an end of an electric wire (We) and is configured to be inserted into a connector insertion hole of the metal case from an opening (501a 1) of the connector insertion hole and to be physically and electrically connected to a counterpart terminal metal fitting of the counterpart device; a housing serving as an accommodation member made of an insulating material that accommodates the terminal metal fitting and the electric wire (We) and leads the electric wire (We) out of the housing, and includes a connector insertion part configured to be inserted into the connector insertion hole from the opening (501a 1) together with the terminal metal fitting; a liquid seal member that is configured to seal a gap between the housing and a rim of the opening (501a 1) in the case; a shield shell that is made of a metal material with an annular flange configured to be opposed to an annular surface (501b 1) around the rim of the opening (501a 1) in an outer wall surface of the case, and a fixed part configured to be fixed to the case; characterized in that the shield shell includes a cylindrical accommodation body accommodating the housing therein, an annular interposed member that is made of a resin material and is configured to be interposed between the flange and the annular surface (501b 1) to be sandwiched between the flange and the annular surface (501b 1), the fixed part includes a collar member configured to abut against the case, and the collar member is formed from a metal material having an ionization tendency equal to that of a metal material having a larger ionization tendency, out of metal materials of the shield shell and the case, or is given surface treatment using a metal material having an ionization tendency equal to that of a metal material having a larger ionization tendency, out of the metal materials of the shield shell and the case. a terminal metal fitting that is physically and electrically connected to an end of an electric wire (We) and is configured to be inserted into a connector insertion hole of the metal case from an opening (501a 1) of the connector insertion hole and to be physically and electrically connected to a counterpart terminal metal fitting of the counterpart device; a housing serving as an accommodation member made of an insulating material that accommodates the terminal metal fitting and the electric wire (We) and leads the electric wire (We) out of the housing, and includes a connector insertion part configured to be inserted into the connector insertion hole from the opening (501a 1) together with the terminal metal fitting; a liquid seal member that is configured to seal a gap between the housing and a rim of the opening (501a 1) in the case; a shield shell that is made of a metal material with an annular flange configured to be opposed to an annular surface (501b 1) around the rim of the opening (501a 1) in an outer wall surface of the case, and a fixed part configured to be fixed to the case; characterized in that the shield shell includes a cylindrical accommodation body accommodating the housing therein, an annular interposed member that is made of a resin material and is configured to be interposed between the flange and the annular surface (501b 1) to be sandwiched between the flange and the annular surface (501b 1), the fixed part includes a collar member configured to abut against the case, and the collar member is formed from a metal material having an ionization tendency equal to that of a metal material having a larger ionization tendency, out of metal materials of the shield shell and the case, or is given surface treatment using a metal material having an ionization tendency equal to that of a metal material having a larger ionization tendency, out of the metal materials of the shield shell and the case.