A connector includes a first connector portion having projection units and at least one locking portion situated between at least one pair of adjacent projection units, and a second connector portion having fitting hole units and at least one portion to be locked, each projection unit of the first connector portion being fitted into each fitting hole unit of the second connector portion as catching a first contact portion of a first circuit board and a second contact portion of a second circuit board that face to be overlapped on each other, the first contact portion and the second contact portion being electrically connected to each other between a lateral surface of each projection unit and an inner surface of each fitting hole unit, while each locking portion is caught on a corresponding portion to be locked.