A circuit board connector for high density line connections for facilitating soldering of connector pins to electrodes on a circuit board. Provided is a connector wherein a first recessed portion and a second projecting portion of a first housing unit engage a first projecting portion and a second recessed portion of a second housing unit, so that the arms of connector pins that extend along the side walls of the recessed portions are electrically connected to the arms of connector pins extending along the corresponding projecting portions, and wherein a height H1 to the top surface of the first recessed portion is shorter than a height H2 to the top surface of the second projecting portion, and a height H3 to the top surface of the first projecting portion, engaging the first recessed portion, is greater than a height H4 to the top surface of the second recessed portion, engaging the second projecting portion. The height differentials provide for a connector structure which is open and readably accessible for soldering connections.