To provide a method capable of manufacturing a bottle having a uniform peripheral wall thickness and a planeform shape, and a hollow molded article having an varyingly adjusted peripheral wall thickness in accordance with a request by blow-molding.
A preliminary molded body 2 to which weighted temperature adjustment is carried out by inserting a preform 1 into a preliminary temperature adjusting die 201 is molded before main blow. A minor axis side wall part 206 is made as a predetermined thin wall thickness so as to decrease a cooling capacity by the contact heat transfer and a major axis side wall part 207 is made as a predetermined thick wall thickness so as to increase a cooling capacity by the contact heat transfer. A thin hardened wall layer is formed on the outer surface of a minor axis side peripheral wall 22 and the content of the rest of the wall remains as a low-viscous high-temperature molten state. A major axis side peripheral wall 21 becomes a high-viscous low-temperature molten state by expanding to a thin wall thickness. By the main blow, after the minor axis side peripheral wall is contacted to a cavity surface, the content part of the minor axis side flows to the major axis side by the expansion of the major axis side to uniform the wall thickness of a final molded body.