The technical problem to be solved by this invention is to develop a polyester resin container that can be retort-processed at a temperature in the range of above 120°C to about 130°C. The object of this invention is to provide a polyester resin container, which is capable of improving the productivity and quality of retort foods, and a molding process thereof. The process of this invention is a double blow molding process, which comprises a primary blow molding step in which a preform is biaxially drawn and blow molded into a primary intermediate product, a thermally shrink-molding step in which the primary intermediate product is heated and forcibly shrink-molded into a secondary intermediate product, and a secondary blow molding step for blow molding the secondary intermediate product into a container, wherein the process is characterized in that a mold temperature higher than 210°C is used in the secondary blow molding step.