To solve a problem wherein solder may be peeled off by concentration of stress on a soldered location when fastening a screw of a printed circuit board after mounting by soldering a terminal block on the printed circuit board and the terminal block may be shaky or may be dropped off from the printed circuit board.

In a screw fastening structure having a screw 1, a terminal block 2 where a hole for inserting the screw 1 is formed, and a fastening component 3 where a screw section engaged with a screw section of the screw 1 is formed, the terminal block 2 and the fastening component 3 are located by holding the printed circuit board 4, the terminal block 2 and the fastening component 3 are mutually fixed by frictional force. and the terminal block 2 or the fastening component 3 is mutually fixed with the printed circuit board 4 by the frictional force.