The present invention relates to a polyester resin composition comprising: (A) a polyester resin containing 5% by mole or more and not more than 86% by mole of a succinic acid unit in the whole of an aliphatic dicarboxylic acid unit; (B) a polyester resin containing 5% by mole or more and not more than 95% by mole of an aromatic dicarboxylic acid unit in all of dicarboxylic acid units; and (C) a polyester resin containing an aliphatic oxycarboxylic acid, wherein the polyester resin composition contains from 10 to 89% by weight of the resin (A) and from 11 to 90% by weight of the resin (B) relative to a total sum of the resins (A) and (B) and contains from 1 to 40% by weight of the resin (C) relative to a total sum of the resins (A), (B) and (C).