Abstract: A method for manufacturing a resin wide-mouthed container includes at least: injection-molding a bottomed preform made of resin; and blow-molding the injection-molded preform. During the injection molding, the preform is injection-molded such that an overhanging section overhanging outward is formed on an outer peripheral section of a first lip section closer to a first body section than a flange section, and while the first lip section, which is provided with the overhanging section, is held by a lip mold, which has a recessed section that engages with the overhanging section, the preform is separated from an injection molding die.

Abstract: A delamination container includes a neck portion having an opening communicating with an inside of the inner layer, a shoulder portion continuously extending in the radial direction from the neck portion, a body portion having a bottomed cylindrical shape, and a constricted portion interconnecting the shoulder portion and the body portion. The diameter of the outer peripheral edge of the shoulder portion is 40 mm or more and 55 mm or less, the axial length from the outer peripheral edge of the shoulder portion to a constricted bottom portion which has the smallest diameter in the constricted portion is 12 mm or more and 25 mm or less, and a ratio of the diameter of the constricted bottom portion to the diameter of the outer peripheral edge of the shoulder portion is 0.80 or more and 0.93 or less.