PURPOSE: To enable to contact all the terminal electrodes with no inadequate connection, by placing a flexible conductive member between the row of terminal electrodes on the substrate and a cap member connected to the board.

CONSTITUTION: Under a cap member 4 is arranged a concave groove 4a to oppose a row of terminal electrodes 7, and between the groove 4a and the row of electrodes 7 is placed a conductive spring 5. This spring 5 is flexible and variable in form in the direction of the radius, and the variable area extends to the all axial area, contacting the all electrodes of the terminal electrode row in an even strength without unevenness of contacting power. Therefore, the all electrodes 7a are contacted to the member 4 through the spring 5, and any failure of adequate connection of electrodes can be prevented.