An object-side lens group has different power factors between the vertical and horizontal directions of a liquid crystal panel, and a projection system as a whole therefore has different focal lengths between the vertical and horizontal directions and hence different magnification factors between the vertical and horizontal directions, whereby the aspect ratio of an image on the liquid crystal panel can be set at a value different from the aspect ratio of an image projected on a screen. That is, the projection system can convert the aspect ratio, which is the ratio of the width to the height of an image. When the distance between a diaphragm and an extreme end surface of the object-side lens group on the screen side satisfies a predetermined condition, at least a certain degree of telecentricity can be provided both in the vertical and horizontal directions.