Provided are a plant-growth laminated film and a plant-growth illumination apparatus that more efficiently provide circularly polarized light used for plant growth. Included are a reflective-type linearly polarizing plate that transmits one of linearly polarized light components of incident light and that reflects the other linearly polarized light component, and a λ/4 plate that converts, into circularly polarized light, linearly polarized light provided by transmission through the reflective-type linearly polarizing plate, wherein the λ/4 plate has an in-plane retardation of 165±40 nm at a wavelength of 660 nm.