Abstract: An ink for marking which is used for marking an outer surface of an article having at least the outer surface formed of a resin and which is excellent in friction resistance and flex resistance after marking is provided. An ink for marking which contains an organic solvent, an oil-soluble dye and an oil-soluble resin, in which the oil-soluble resin has at least two types of acrylic resins mixed; in the aforementioned at least two types of acrylic resins, a total of an acid value and a hydroxyl value of at least one type of acrylic resin is 10 or less; and in the aforementioned at least two types of acrylic resins, a total of an acid value and an hydroxyl value of the other at least one type of resin is 70 or more.

Abstract: In each of an organic solvent, an oil-soluble dye and an oil-soluble resin to be contained in an ink for marking, and a resin adopted in an article to be marked with the ink for marking, it is necessary that absolute values of differences between mutual solubility parameters are not more than constant values, respectively.