The invention provides a method for a continuous production of biodegradable aliphatic/aromatic polyester copolymer, and the method comprises the steps of: reacting an aliphatic dihydroxy compound and an aliphatic dicarboxylic acid at 185[deg.C] or lower in a primary ester reaction; continuously reacting the product obtained from the previous step in a secondary ester reaction; reacting the product obtain from the previous step in a continuous primary polycondensation reaction and obtaining a preliminary polymer; reacting the preliminary polymer in a continuous secondary polycondensation reaction and obtaining a product having a melting index (MI) of 15-25 g/10min; and reacting the product obtained from the previous step in a continuous tertiary polycondensation reaction, and the biodegradable aliphatic/aromatic polyester polymer is produced by adding an aromatic dicarboxylic acid in the step for the first ester reaction or in the step for the continuous second ester reaction.