To provide a composite container and a method for manufacturing the composite container suitable for retort treatment of contents.

The method for manufacturing the composite container manufactured by laminating an inner layer side plastic molding with a flange part in an opening, an intermediate base material, and an outer layer side plastic molding with a flange part in an opening, in this order to seal the intermediate base material, includes inserting the intermediate base material inside the outer layer side plastic molding, heat-bonding the inner peripheral edge of the outer layer side flange part to the opening edge of the intermediate base material, then inserting the inner layer side plastic molding inside the intermediate base material, heat-bonding the outer layer side flange part to the inner layer side flange part excluding a part to form a composite container intermediate product, placing the whole composite container intermediate product under reduced pressure to eliminate gas left between the inner and outer layer plastic moldings, and heat-bonding all of the outer layer side flange part and inner layer side flange part while keeping the whole composite container intermediate product under reduced pressure.