A biodegradable polyester resin prepared by a method comprising an esterification reaction and a condensation polymerization reaction of:
- dimethyl terephthalate and adipic acid in a weight ratio of 40:60 to 60:40 as an acid component,
- 1,4-butanediol as a glycol component,
- polyglycerol succinate as a reaction rate control agent, and
- polyglycerol furanoate as a molecular weight increasing agent,
- wherein the biodegradable polyester resin has:
- a number average molecular weight of 70,000 or more,
- a weight average molecular weight of 150,000 or more,
- an acid value of 0.4 to 0.8 mg-KOH/g, and
- a tensile strength of 400 kgf/cm2 or more.