PURPOSE: To reduce man-hours for assembly and the time for operations and lessen damages likely to be given to a contact piece when connector is inserted or drawn off, by furnishing a resilient arm pinching a circuit base board from the back side of a housing and being provided with a projecting piece at the foremost thereof, and equipping the base board with a detention part where the projecting piece is detained.

CONSTITUTION: When pinching with an arm 14a is made from the edge 5a side of a circuit base board 5, a projecting piece is detained with a hole 17, and a connector 11 is mounted at the edge 5a. In this condition it is placed in a heating furnace, and a contact hole 13 is fusion attached to a circuit pattern 6. Because the connector 11 can be mounted merely by detaining the projecting piece with the hole 17, it is not required to make troublesome fixing works using bolt and nut, which allows reducing the man-hours for assembly and the time for works. Further because the arm 14a is made of a material having toughness and resilience, external force applied to the soldered joint surfaces of the circuit pattern 6 and the contact piece 13 at connector inserting or drawing-off can be relieved, and durability of the contracting force at the joint surfaces be maintained in satisfactory performance, and damages of the contact piece 13 be reduced.