The present invention is a three-dimensional-modeling soluble material to be used as a material of a support member for supporting a three-dimensional object when the three-dimensional object is produced with a 3D printer that employs a fused deposition modeling method. The three-dimensional-modeling soluble material contains a polyester resin comprising: an aromatic dicarboxylic acid monomer unit A having a sulfonic acid base; a dicarboxylic acid monomer unit B that does not have a sulfonic acid base; and a diol monomer unit, wherein the proportion of the aromatic dicarboxylic acid monomer unit A in the total of all dicarboxylic acid monomer units is 10 to 70 mol %. The present invention can provide a three-dimensional-modeling soluble material to be used for a support member, which material is suitable for production of a three-dimensional object by the FDM method, has moisture-absorption resistance, has a high rate of dissolution in neutral water, and can be quickly removed from a three-dimensional object precursor without using a strong alkali aqueous solution.