A wide mouthed container of synthetic resins for a paint, wax and the like, formed thinly in the body portion thereof by injection stretch blow molding is provided. A mouth portion of the wide mouthed container is of large diameter and comprises an internal wall integral with a body portion having a bottom, a belt shaped external wall integrally formed on the outside of the internal wall via a joint portion of required width to be in H-shape, and an upper and lower annular grooves between both the walls sectioned by the joint portion. The body portion is stretch blow molded thinly from the underside of the internal wall to a position where the lower edge of the external wall touches the body portion to form the side surface of the body portion on the same level as said external wall and to form the lower annular groove into a hollow in the lower part of the mouth portion. A plurality of ribs for preventing the deformation of the joint portion in stretching the body portion are integrally formed aslope onto a corner between the under surface of said joint portion at its external wall side and the inner surface of the external wall to provide a required number of the ribs in the lower annular groove at a regular interval.