Abstract: The present disclosure provides a printed circuit board connecting structure including a first printed circuit board, a protection layer, an ACF (anisotropy conductive film), and a second printed circuit board. The first printed circuit board includes a first circuit. The protection layer covers a first area of the first circuit. The ACF covers a second area of the first circuit and extending to the protection layer. The second printed circuit board includes a second circuit facing the first circuit. The second printed circuit board partially overlaps with the ACF on the second area of the first circuit, and there is a gap between the second printed circuit board and the protection layer.