A natural ventilation apparatus 1 includes a window frame 2 which is installed in a building; a framed panel 4 disposed in an opening portion 3 defined by the window frame 2; and opening/closing means 5 for opening and closing the opening portion 3 on the basis of an air current. The opening portion 3 is adapted to be opened by the opening portion opening movement of the framed panel 4 moving toward a building exterior 7 side, and to be closed by the opening portion closing movement of the framed panel 4 moving toward a building interior 8 side.