a form - retaining container made of synthetic plastic material and apparatus for its manufacture in which a plastic material is fed in liquid state onto a male member to provide a layer on the male member constituting a blank for the container . the layer is cooled to prevent crystallization of the material . the thus cooled blank is placed into a mold cavity having an interior configuration corresponding to the desired outer shape of the container to be produced . the layer is inflated into conformity with the mold cavity . the configuration of the mold cavity is such that the blank undergoes biaxial stretching in a middle region of the container by at least 1 . 5 times while the mouth and part of the bottom of the container will be formed by biaxially stretching the blank less than 1 . 5 times . the inflated blank is then heated until curing is completed and then the blank is removed from the mold .