Second reference section 85 is arranged between two adjacent electrodes 82 among the multiple electrodes 82. Second reference section 85 includes stopping claw 85a and regulating surface 85b. Here, as shown in FIG. 3A, circuit board 70 is provided with stopping hole 72 that pierces circuit board 70 in the thickness direction (vertical direction of FIG. 3A). As shown in FIG. 3B, stopping claw 85a is inserted through stopping hole 72 of circuit board 70 and engages with the lower surface of circuit board 70. By this, stopping claw 85a prevents pin section 84a inserted into positioning hole 71 of circuit board 70 from coming out. Also, similar to regulating surface 84b of first reference section 84, regulating surface 85b of second reference section 85 contacts an upper surface of circuit board 70 when stopping claw 85a has been inserted by a specified amount in stopping hole 72, such that relative movement of stopping claw 85a with respect to stopping hole 72 is regulated.
