A circuit board connecting device comprising an insulating housing, a plurality of conductive contacts arranged on the insulating housing, and a resilient shell member attached to the insulating housing, wherein the resilient shell member includes a strip-shaped portion surrounding partially a board-facing surface portion of the insulating housing so as to cause an inner surface portion thereof to come into resilient contact with an outer surface portion of a mate connecting device, a pair of bent projecting portions each elongating to be bent from an end portion of the strip-shaped portion for projecting in a direction remote from the insulating housing, and a pair of extending portions each extending further to be bent from an end portion of the bent projecting portion so as to be opposite to the strip-shaped portion, so that the whole of the strip-shaped portion, the bent projecting portions and the extending portions constitute a spring member.