Synthetic resin container

A synthetic resin container, comprising a mouth portion, a shoulder portion, a body portion and a bottom portion, wherein

• the body portion is formed into an angular cylindrical shape having a polygonal cross section shape and has one or more concave groove portions formed along a circumferential direction;
• and
• the concave groove portions being formed in such a manner that:
• a cross section shape of a site in which the concave groove portion is formed is similar to a cross section shape of a site formed into the angular cylindrical shape of the body portion, and
• when the cross section shape of the site in which the concave groove portion is formed and the cross section shape of the site formed into the angular cylindrical shape of the body portion are superimposed on each other on the same plane, respective apexes of the cross section shape of the site in which the concave groove portion is formed internally contact with respective sides of the cross section shape of the site formed into the angular cylindrical shape of the body portion.