An illumination apparatus and an exposure apparatus that achieves higher quality exposure to light and higher operating speed even where the ratio Hx/Hy between the transverse dimension Hx and the longitudinal dimension Hy of the plane of optical modulation of a two-dimensional optical space modulator is 1.5 or above, for instance, are to be provided. The focal distance fx in an x-direction and the focal distance fy in a y-direction of a second optical system that guides light emitted from an integrator to a two-dimensional optical space modulator are made different, in a ratio of fx/fy=1.6, for instance. In this way, the number of rod lenses in the integrator can be made equal between transverse and longitudinal directions and the value of Hx/Hy can be made 2.5 by bringing the aspect ratio dx:dy of rod lenses to 1.6:1, close to 1.