An aligner to expose any exposure area includes an exposure light source that emits an exposure beam having a specified width to expose the exposure area to light; a douser having a width corresponding to at least the width of the exposure beam; and a shading unit to prevent the exposure beam from reaching an area other than the exposure area by driving the douser to shut off part or all of the exposure beam. The aligner is capable of forming different exposure areas with high density and having a structure suitable to reduce the size of the entire unit.