An aperture module includes a rotation plate disposed on a base, a moving portion that moves linearly to rotate the rotation plate, and blades linked to the rotation plate to form an aperture having a variable size. The blades include at least two small-aperture blades that are contracted inwardly toward an optical axis to form the aperture having a first size and at least two medium-aperture blades that are contracted inwardly toward the optical axis to form the aperture having a second size larger than the first size. The at least two small-aperture blades and the at least two medium-aperture blades are extended outwardly away from the optical axis to form the aperture having a third size larger than the second size.