To reduce a volume of an empty bottle after contents in a resin bottle have been consumed for convenience of a consumer life and also to make a form excellent in collection efficiency for recycling.

A guide protrusion 6 is provided on a cut line 2 and a cut line 3 of the resin bottle, so that a constant position can be cut on the bottle. An uncut part 8 is provided on a part of the cut line 2, so that upper and lower parts of the bottle may not separate after cutting. Other equivalent bottles can be inserted and stacked in the cut bottle.