Synthetic resin container

A synthetic resin container comprising a mouth that serves as a dispensing opening for contents, a body that is continuous with the mouth via a shoulder, and a bottom that closes a lower end of the body, wherein

• the body includes a pair of main walls arranged so as to face each other with a gap therebetween, a pair of side walls arranged so as to face each other with a gap therebetween, and corner walls that couple respective ends of the main walls that extend along a central axis of the synthetic resin container to respective ends of the side walls that extend along the central axis of the synthetic resin container, and
• all of the corner walls are provided with U-shaped ribs that are formed in a substantially U-shape, that are formed only within a surface of the corner wall, and that are concave toward an inner side in a thickness direction of the corner wall,
• wherein each of the U shaped ribs includes a longitudinal groove extending substantially in a vertical direction, horizontal grooves extending substantially in a horizontal direction from both ends of the longitudinal groove in the vertical direction, an opening at an end opposite from the longitudinal groove between the horizontal grooves, and a central protrusion surrounded by the longitudinal groove and the horizontal grooves, and the central protrusion is at least partially present between:
• (i) the horizontal grooves in the vertical direction and
• (ii) the longitudinal groove and the opening in the horizontal direction.