A polyglycolic acid-based resin composition is formed by adding a relatively small amount of aromatic polyester resin to a polyglycolic acid resin. The thus-formed composition is provided with remarkably improved moisture resistance stability and hot-melt processability, and further improved stretchability, while retaining the excellent properties as represented by gas barrier property of the polyglycolic acid resin. As a result of stretching by utilizing the improved stretchability, a shaped product having an improved transparency can be obtained.