Socket and inter-board connectors of the board between the connectors

To provide a substrate between the connectors the lower profile and narrow pitch can be easily achieved. A board-to-board connector 1 includes a header 3 having a plurality of header contacts 6a and 6b, and a socket 5 having a plurality of socket contacts 19a and 19b. Socket contacts 19a and 19b is provided with a flat side of the socket connecting part 28 which extends in the longitudinal direction. The socket-side connecting portion 28, the insertion fixing hole 31 extending in the longitudinal direction is provided. Insert fixing hole 31 includes an insertion portion 31a, and the corresponding press-fit portion 31b projecting portions 17 of the header contact 6a and 6b is press-fitted by being moved in the longitudinal direction of the insertion fixing hole 31 is inserted into this constructed. .FIELD 5