To provide a sack of a novel structure for use in garbage disposal capable of improving efficiency and safety in feeding garbage thereinto by promptly and stably forming and maintaining the shape of its garbage feed port.

The sack for use in garbage disposal constituted of a cylindrical body 12 made from an air-permeable and water-impermeable material is characterized in that a pair of annular holders 16, the shape of which is plastically deformable by hand, are each attached to end-openings 14a, 14b of the cylindrical body 12 respectively to keep one opening 14a of the cylindrical body 12 closed allowing a garbage decomposing agent 24 to stay therein and to keep the other opening 14b thereof opened by the annular holders 16 enabling itself to serve as a garbage feed port, and is further characterized in that the cylindrical body 12 can be used in a vertically reversed state as well.