A circuit constituent 10 comprises a circuit board 11 on which a switching member 13 is implemented and a bus bar 12 wired along the circuit board 11, and a case 20 is provided with a frame 21 arranged on the circuit board 11 and fixed along its peripheral edge and a cover 24 assembled to the frame 21 so as to cover the circuit board 11. A plurality of first terminal portions 14 constructed by bending the ends of the bus bar 12 substantially in the L shape are arranged side by side along the frame 21, and a falling restriction portion 36 provided at a front edge portion 24F of the cover 24 restricts falling deformation of the first terminal portion 14. By locking displacement restricting portions 30, 37 provided at the outer edge portions of the frame 21 and the cover 24 with each other, displacement of the cover 24 in the direction separated from the first terminal portion 14 with respect to the frame 21 is restricted, and falling deformation of the first terminal portion 14 can be surely prevented.