An exposure apparatus which illuminates a reticle with illumination light from a light source and projects light from the reticle onto a substrate to expose the substrate to light is disclosed. The apparatus comprises a shutter located on a path of the illumination light, a detector configured to detect a dose to the substrate, and a controller configured to control operation of the shutter. In a first exposure mode which uses illumination light with a first light intensity, the controller controls an open time of the shutter based on an output from the detector, and to store the open time. In a second exposure mode which uses illumination light with a second light intensity higher than the first light intensity, the controller controls a speed of the shutter based on the stored open time.