A second group has different power in the vertical direction and the horizontal direction of the liquid crystal panel. Therefore, the horizontal-to-vertical ratio of the image of the liquid crystal panel and the horizontal-to-vertical ratio of the image projected on the screen can be set to be different. That is, the projection optical system is able to convert the aspect ratio which is a ratio of width and height. At this time, at the time of converting the aspect ratio, that is, at the time of switching the projection state, it is possible to adjust the position of the image on the screen through a zoom operation or a shift operation of the first driving mechanism or the fourth driving mechanism.