Disclosed is a board reinforcing structure for reinforcing a circuit board in which an electronic component is mounted on a first surface, the electronic component having an electrode arranged in a rectangular-shaped region on the first surface. The board reinforcing structure includes a reinforcing member bonded to positions corresponding to corner parts of four corners of the rectangular-shaped region on a second surface provided on a side opposite to the first surface of the circuit board. In the board reinforcing structure, corresponding one of notches is formed in the reinforcing member at a position corresponding to one of the corner parts of the four corners of the rectangular-shaped region, and at least two apexes of the reinforcing member directed to an outside are formed to shape a contour thereof with the one of the notches.