To suppress a hunting phenomenon of an ink film thickness on the surface of paper on the occasion of color matching and to lessen a spoilage of paper, regarding a method and equipment for regulating an ink supply of a printing machine which regulates the ink supply to a printing plate on the basis of values of density and color of printed matter.

An allowable density difference for a measured density difference is set in a plurality of kinds and made selectable before the color matching. When "0" is set as an allowable value condition, the amount of opening of a corresponding ink key is regulated only in the case when the measured density difference is larger than a first allowable density difference. When "1" is set as the allowable value condition, the amount of opening of the corresponding ink key is regulated only in the case when the measured density difference is larger than a second allowable density difference (>the first allowable density difference). When "2" is set as the allowable value condition, the amount of opening of the corresponding ink key is regulated only in the case when the measured density difference is larger than the first allowable density difference and smaller than the second allowable density difference.