To provide a method for manufacturing a blow integral, light-weight and high-strength molding made of a CFRP having an entirely not-uniform and complicated part section and a blow molding.

The method for manufacturing the blow molding made of the CFRP comprises (1) a manufacturing step of a core for forming a passage of a cooling water passage component, (2) a CFRP laminating step of laminating a sheet-like CFRP of a mold release tape on a periphery of the core, (3) a melt curing step of melt curing the CFRP by heating the core in a pressurized state, and (4) a core melting and finishing step of melting the core from the molding after curing to a final molding conducting a finishing work of the molding. The method may also comprise a secondary CFRP laminating step of mounting a necessary member on an intermediate CFRP molding and a second time sheet-like CFRP laminating, and a second melting and curing step of heating the intermediate product again in a pressurized state and second time melting and curing the CFRP, as needed between the steps (3) and (4).