To provide an eco bag or carrier bag which can float on water in order to use it as a buoyancy bag at the time of a flood although eco bags are usually used as shopping bags.

An eco bag or carrier bag which can float on water is made from totally waterproof material; a totally waterproof fastener is provided at the opening of the bag; carrying straps are fitted at the front and the back of the bag, respectively, or across the front and the back so that it can be shouldered; a length-adjustable belt for stabilizing shoulder straps, is provided at the front; wires which can widen the bag, are provided at both edges of the bag, and wire clips which can help widen the tips of each wire are provided; gussets are provided at the lower part of the bag; a bag closing tool for keeping the bag in a folded state, is provided at the upper part; all fitting and closing areas required to be waterproof are totally waterproof or have waterproof specifications; and a storage pocket is furnished. Therefore, when the fastener at the opening is closed, the bag can be a totally waterproof bag, and be used as a buoyancy bag.