A first connector of a pair of connectors fitted has a shell accommodating a second connector of the connectors. By fitting both connectors, female terminals and male terminals are connected to each other. The second connector includes an outer case removably inserted in the shell, an inner case incorporated in the outer case and inserting female terminals therein, a cylindrical body accommodated rotatably in the outer case, and a locking member with an operating lever formed on the cylindrical body. An abutting-on portion in the cylindrical body on the side of the shell has a first magnetic substance. Another abutting-on portion in the shell on the side of the cylindrical body has a second magnetic substance having a polarity opposite to that of the first magnetic substance.