A stereo lithography apparatus includes a modeling tank that retains a photo-curable resin and in which a light transmission plate is provided on a bottom surface of the modeling tank, a light irradiation unit that irradiates light for curing the photo-curable resin, a platform is provided so as to be capable of being raised and lowered with respect to the modeling tank, bulkheads each of which is formed in a cylindrical shape and forms an airtight space in cooperation with the platform, a raising and lowering control unit that forms a photo-curable resin layer having a predetermined thickness between the light transmission plate and both a lower surface of each of the bulkheads and a lower surface of the space, and an irradiation control unit that forms a cured layer by irradiating the photo-curable resin layer with the light corresponding to a cross-sectional shape of the modeling object at a predetermined height position.