To provide a polymer composition derived from an organism so as to adapt to the recycling-oriented society and exhibiting excellent chemical functionality compared with petroleum-derived conventional functional resins and to provide uses thereof.

The biodegradable highly functional polymer composition comprises ≥50 wt.% of at least one or more kinds of components selected from tartaric acid and citric acid and is obtained by carrying out polymerization or copolymerization, as necessary, using a chain extender.