A method for recovering a water-soluble polyester resin contained in a support material from an effluent in which the support material is dissolved and/or dispersed that is generated when a precursor of a three-dimensional object containing a three-dimensional object and a support material is brought into contact with an aqueous cleaning agent to remove the support material from the precursor of a three-dimensional object in a manufacturing process of a three-dimensional object by fused deposition modeling, comprising: a metal salt addition step of adding, to the effluent, at least one metal salt selected from the group consisting of a calcium salt, a magnesium salt, a sodium salt, a potassium salt, an aluminum salt, and an iron salt and selected from the group consisting of metal salts having a solubility in water of 1 g/100 cm 3 or more; a water-soluble polyester resin precipitation step of subjecting the effluent containing the metal salt to a heat treatment at 30°C or more after the metal salt addition step to precipitate a water-soluble polyester resin; and a water-soluble polyester resin recovery step of separating and recovering the precipitated water-soluble polyester resin from the effluent after the water-soluble polyester resin precipitation step, wherein the amount of the metal salt added in the metal salt addition step is 5 parts by mass or more and 1,000 parts by mass or less to 100 parts by mass of the water-soluble polyester resin dissolved and/or dispersed in the effluent when the metal salt is at least one metal salt selected from the group consisting of a calcium salt, a magnesium salt, an aluminum salt, and an iron salt; and the amount of the metal salt added in the metal salt addition step is 100 parts by mass or more and 1, 000 parts by mass or less to 100 parts by mass of the water-soluble polyester resin dissolved and/or dispersed in the effluent when the metal salt is at least one metal salt selected from the group consisting of a sodium salt and a potassium salt, wherein the water-soluble polyester resin has an aromatic dicarboxylic acid monomer unit A with a sulfonate group, and the content of the sulfonate group in the water-soluble polyester resin is 0.5 mmol/g or more. a metal salt addition step of adding, to the effluent, at least one metal salt selected from the group consisting of a calcium salt, a magnesium salt, a sodium salt, a potassium salt, an aluminum salt, and an iron salt and selected from the group consisting of metal salts having a solubility in water of 1 g/100 cm 3 or more; a water-soluble polyester resin precipitation step of subjecting the effluent containing the metal salt to a heat treatment at 30°C or more after the metal salt addition step to precipitate a water-soluble polyester resin; and a water-soluble polyester resin recovery step of separating and recovering the precipitated water-soluble polyester resin from the effluent after the water-soluble polyester resin precipitation step, wherein the amount of the metal salt added in the metal salt addition step is 5 parts by mass or more and 1,000 parts by mass or less to 100 parts by mass of the water-soluble polyester resin dissolved and/or dispersed in the effluent when the metal salt is at least one metal salt selected from the group consisting of a calcium salt, a magnesium salt, an aluminum salt, and an iron salt; and the amount of the metal salt added in the metal salt addition step is 100 parts by mass or more and 1, 000 parts by mass or less to 100 parts by mass of the water-soluble polyester resin dissolved and/or dispersed in the effluent when the metal salt is at least one metal salt selected from the group consisting of a sodium salt and a potassium salt, wherein the water-soluble polyester resin has an aromatic dicarboxylic acid monomer unit A with a sulfonate group, and the content of the sulfonate group in the water-soluble polyester resin is 0.5 mmol/g or more. <EOS>