There are included a CAN package (2) having a stem (22) and lead pins (23a and 23b) protruding from the stem (22), and a board (3) having pads (33a and 33b) for connecting lead pin. The CAN package (2) has a slot (222) provided in a surface of the stem (22) from which the lead pins (23a and 23b) protrude. One end of the board (3) is inserted into the slot (222), and the pads (33a and 33b) for connecting lead pin are electrically connected to the lead pins (23a and 23b).