PURPOSE: To provide a bag body for cushioning which is decomposed in the last even when it is discarded by a method wherein for a bag body to enclose a gas airtightly, which gives cushioning reaction to the external pressure, the bag body is formed of a decomposable material.

CONSTITUTION: The bag body for cushioning 1 has a bag body 11 which is formed into a balloon shape so as to enclose a gas A, and is generally formed by blow molding, etc., and the bag body 11 is formed of a decomposable material. The decomposable material is formed of a decomposable plastic, especially a polyolefin resin such as decomposable polyethylene resin or decomposable polypropylene, etc., polyvinyl alcohol or decomposable polyester. The decomposable polyolefin resin's major component is polyolefin, and it is a resin which can be decomposed by light or microbe.