An overhead projector provides an unobstructed view of projected images by minimizing the vertical dimension of the projector and provides sufficient brightness of projected images by minimizing the loss of light. The light emitted from a light source housed in the body of the projector is reflected by a first reflection mirror and directed, through a transparent stage on which a transparent original is placed, to a second reflection mirror. Meanwhile, on the transparent stage, the principal ray axis of the light beam forms an angle .theta. with respect to the center axis of the surface of the transparent original. After reaching the second reflection mirror and being reflected thereby, the light is condensed into a projection lens unit, and is projected therefrom onto a screen to form thereon an image of the transparent original.