An ink supply amount adjustment method for a printing press includes steps of measuring the density value of each density measurement patch printed in a range corresponding to each ink fountain key on a printed printing sheet, obtaining the opening ratio of each ink fountain key in preliminary ink feeding, based on the difference between the measured density value of a patch and a preset reference density value, and the current opening ratio of each ink fountain key or image data in the range corresponding to each ink fountain key, and performing the ink feed operation of an ink ductor roller while printing is suspended, after setting the opening ratio of each ink fountain key to the obtained opening ratio in preliminary ink feeding. An ink supply amount adjustment apparatus for a printing press is also disclosed.