A cooling apparatus includes a conveying means which conveys a resin composition formed into a sheet shape along a direction parallel to a surface of the sheet-shaped resin composition and a cooling means which cools the resin composition being conveyed by the conveying means. A temperature of the resin composition just before being cooled by the cooling means is in the range of 40 to 60° C. and the cooling means has a cooling ability to cool the resin composition such that a cooling rate of the resin composition is in the range of 0.2 to 5° C./min. Further, the cooling means includes a fan section having at least one outlet port which discharges cooling air of which temperature is in the range of −40 to 0° C. to the resin composition.