A catadioptric optical system includes a first imaging optical system that includes a catadioptric part that collects a light beam from an object to form an intermediate image of the object, and a second imaging optical system that includes a refractive part that images the intermediate image on an image plane. The first imaging optical system includes a first optical element, a second optical element, and a negative lens in an optical path between the first and second optical elements, and the first and second optical elements are disposed so that reflection parts of the first and second optical element face each other. A power φn of the negative lens, radii of curvature R1n and R2n of lens surfaces of the negative lens at an object side and an image side, respectively, and a power φ1 of the first imaging optical system are appropriately set.