A pattern image generation device generates a pattern image, and at least a part of the pattern image which has been generated or the pattern image which is generated and is formed on an object is photoelectrically detected by a detection system. Then, a correction device corrects design data that should be input to the pattern image generation device based on the detection results. Accordingly, a pattern image is generated on an object by the pattern image generation device corresponding to the input of the design data after the correction, and because the object is exposed using the pattern image, a desired pattern is formed on the object with good precision.