Even when a connection board has a large thickness tolerance, a stable connection is achieved by absorbing the tolerance so as to stabilize a contact pressure between the connection board and contacts. In a unit in which electrode groups of a connection board are in pressure contact with elastic contacts formed integrally with an inner housing to connect thereto, the inner housing is provided inside an outer case of a card edge connector through an elastic member to be freely movable forward and backward in a thickness direction of the connection board. The positions of the elastic contacts are adjusted by forward or backward moving the inner housing in accordance with the thickness of the connection board inserted into board insertion slots, so a pressure contact force with the elastic contacts is substantially equalized, irrespective of the size of the thickness of the connection board.