A reflective-type projection optical system has 8 reflective mirrors that form a reduced image of a first surface on a second surface. A first reflective imaging optical system (G1) forms an intermediate image of the first surface, and a second reflective imaging optical system (G2) forms an image of the intermediate image on the second surface. The first reflective imaging optical system has, from the first surface side in order of light beam incidence, a first reflective mirror (M1), a second reflective mirror (M2), a third reflective mirror (M3), and a fourth reflective mirror (M4). The second reflective imaging optical system has, from the first surface side in order of light beam incidence, a fifth reflective mirror (M5), a sixth reflective mirror (M6), a seventh reflective mirror (M7), and an eighth reflective mirror (M8). At least one of the reflective surfaces of these 8 reflective mirrors is composed of a spherical surface.