Circuit device and connecting member

Circuit device capable of forming a terminal portion with a narrow pitch, to provide a production method and the connecting member of circuit devices. Circuit device 10 includes a first circuit board 11 and the second circuit board 15 which is disposed along a thickness direction of the substrate 12, 16, interposed between the first circuit board 11 and the second circuit board 15 connected and a member 20, the terminal portion 21 provided on the connecting member 20 first circuit board 11 and the second circuit board 15 are electrically connected. The circuit device 10 is integrally formed by the terminal portion 21 performs a plating process on the frame 25.