(57) [Problems to be Solved] A fountain solution composition for lithographic printing, which is superior in preventing dirt at a non-image area of a lithographic plate, is provided. Especially, provided is a fountain solution composition for lithographic printing, which can attain high quality printing by mitigating dirt after a break caused by dirt at a non-image area of a plate at a restart of printing after a stop of a printing press, and further by suppressing decrease in the ink density at an image area, even when the component concentration of the fountain solution is increased.
[Solution] A fountain solution composition for lithographic printing characterized by comprising a star polymer having at least one hydrophilic group; the fountain solution composition for lithographic printing, wherein the star polymer is a star polymer having 3 branches to 10 branches; the fountain solution composition for lithographic printing, wherein 3 branches to 10 branches of polymer chains are branched from a skeleton through sulfide bonds in the star polymer.; the fountain solution composition for lithographic printing, wherein the star polymer is a polymer having 3 branches to 10 branches of polymer chains branched from a skeleton through sulfide bonds, the polymer being obtained by polymerizing an ethylenic unsaturated monomer in the presence of a multifunctional thiol; the fountain solution composition for lithographic printing, wherein the star polymer further comprises at least one substrate adsorptive group; and the fountain solution composition for lithographic printing as a concentrated fountain solution composition.