A first connector is surface mounted to a mount surface of a printed circuit board through a plurality of lead terminals and at least one peg element. A second connector is engageable and disengageable relative to the first connector through insertion and removal, respectively, of one of the first connector and the second connector relative the other one of the first connector and the second connector. At least one of the first connector and the second connector includes at least one engaging projection, which projects from an outer surface of the at least one of the first connector and the second connector and is engaged with the printed circuit board.