PURPOSE: To enable laying many containers one upon another vertically as well as side by side laterally without causing them to deform so as to increase the storing efficiency in their transportation, storage, etc.

CONSTITUTION: At the top of a substantially rectangular, pillar-shaped main body part horizontal planes 25 are formed at least in the vicinities of the four vertexes of the rectangle. On the other hand, in the lower part of the main body part contact planes 26 are provided, which, when a number of plastic containers 10 of this kind are laid one upon another vertically, come in contact with the aforementioned horizontal planes at least in the vicinities of the four vertexes; a recess 20 which admits the mouth 11 at the top of the container and the cap fitted over it is also provided. As a result, the load from a container 10H placed above, inclusive of the liquid contents, is born only on the parts at the corners of the rectangle, so that the container 10L placed under can bear up the load from many containers without undergoing deformation or buckling.