To prepare an agricultural multifilm which does not undergo more rapid deterioration at portions buried in the soil than the other portions, to obtain a biodegradable polyester resin composition for manufacturing the same and to provide a molded product thereof.

The biodegradable polyester resin composition comprises an aliphatic polyester resin (A) comprising 35.0-49.99 mol% each of recurring units represented by the formulae (1): -CO-R1-CO- (wherein R1 is a 1-12C bivalent aliphatic group) and (2): -O-R2-O- (wherein R2 is a 2-12C bivalent aliphatic group) [provided that (1) and (2) add up to 70.0-99.98 mol% and that (1) contains 1-25 mol% of a recurring unit derived from adipic acid] and 0.02-30.0 mol% of a recurring unit represented by the formula (3) -CO-R3-O- (wherein R3 is a 1-10C bivalent aliphatic group) [provided that (1), (2) and (3) add up to 100 mol%] and having a molecular weight of at least 50,000, and a polyester resin (B) having a melting point or Tg higher than those of the resin (A) by at least 5°C.