To obtain a higher buckling strength when a plastic container has the same product weight (product thickness) as that of a conventional product, the same buckling strength as that of a product with no thinning when the product weight is reduced for thinning to enable reduction of a raw material cost by a part of thinning, and reduction of the cost of the whole product when the product weight is reduced for thinning, as cooling time of the molded article is shortened, the molding cycle can be shortened.

Reinforcing ribs are provided at positions where buckling stress concentrates in the plastic container.