A coupling structure between a circuit board and a frame member according to the present invention includes: the frame member made of a metal material; and the circuit board set in the frame member and having a land portion soldered to the frame member, in which a solder reinforcing member that is put on the land portion and is solderable is provided at a corner formed by the frame member and the circuit board, and the frame member, the land portion, and the solder reinforcing member are soldered at the corner.