To ensue connecting reliability without complicating a structure and increasing a cost and to improve the mechanical strength of an insulating resin for a connector even if the connection terminal of a FPC is fitted in/out many times.

A main board 1 which has a plug portion 4 forming by arranging a plurality of the contact terminals 3 of preset pitch near the edge is electrically connected to a FPC 7 provided with a fixed socket portion 8. On the socket portion 8, a contact terminal with the same pitch as that of the contact terminal 3 of the main board 1 is arranged. Fitting grooves 5 are provided near both ends of the plug portion 4 of the main board 1 so that the edges 8a on both sides of the socket portion 8 can be put in contact with and supported by the plug portion 4 of the main board 1 when the socket portion 8 of the FPC 7 is mounted thereon.