A preform of injection-molded PET has a body wall thickness of 3.0-4.5 mm. The preform is high-temperature mold-released from an injection cavity mold and an injection core. Pre-blowing of the preform is restricted at 5±0.5 seconds after the mold release, at a temperature of 112-117° C. of the pre-blow mold, and for a pre-blowing time of 0.5-1.0 second. Air blowing is applied to expand only the body of the preform. Stretch blow molding is performed restrictively at 3-4 seconds after the mold release from the pre-blow mold, at a temperature of 103-107° C. of the blow mold, and for an air blowing time of 6-9 seconds, thereby stretch blow molding the preform into a bottle and simultaneously heat setting to impart heat resistance to the bottle.