Manufacturing method and manufacturing apparatus for delamination container

A manufacturing apparatus for a delamination container, the manufacturing apparatus comprising:

• a first injection molding unit configured to injection-mold a first layer of a preform having a bottomed cylindrical shape from a first resin material as a first injection molding;
• a second injection molding unit configured to inject a second resin material different from the first resin material to form a second layer on an inner peripheral side of the first layer as a second injection molding;
• and
• a blow molding unit configured to blow-mold, in a state of having residual heat from injection molding, the preform obtained by the second injection molding portion, to manufacture the delamination container,
• wherein the first injection molding unit includes a first protrusion portion that forms a first recess portion in at least part of the first layer,
• the second injection molding unit includes a second protrusion portion that is inserted into the first recess portion,
• the second protrusion portion forms, in the preform, a second recess portion, which penetrates the first layer and through which a surface of the second layer is exposed,
• the blow molding unit stretches the second recess portion to form an air introduction hole in an outer layer of the delamination container,
• in the first injection molding, a thin film portion having a thickness is formed in part of the first layer, and
• in the second injection molding, the second resin material is guided to the inner peripheral side of the first layer by breaking the thin film portion by injection of the second resin material.