An ink supply method comprising the steps of: decreasing ink in an ink roller group by scraping and removing the ink by an ink scraping member after an end of a print job including adjusting an amount of ink supplied from an ink fountain to an ink fountain roller by adjusting an opening amount of an ink fountain key (4-1 to 4-n) and supplying the ink supplied to the ink fountain roller to a printing plate via the ink roller group by a feed operation of an ink ductor roller; calculating the opening amount of the ink fountain key (4-1 to 4-n) corresponding to an image of a printing plate of a next print job; obtaining, as a correction value of the opening amount of the ink fountain key (4-1 to 4-n), a correction value according to an index value representing an ink supply amount corresponding to an image in an area of a printing plate of a preceding print job corresponding to the ink fountain key (4-1 to 4-n); correcting the calculated opening amount of the ink fountain key (4-1 to 4-n) corresponding to the image of the printing plate of the next print job with the obtained correction value of the opening amount of the ink fountain key (4-1 to 4-n); wherein the step of correcting with the correction value includes a step of adding the obtained correction value to the calculated opening amount; setting the opening amount of the ink fountain key (4-1 to 4-n) to the corrected opening amount; and forming, on the ink roller group, an ink film thickness distribution corresponding to the image of the printing plate of the next print job by performing the feed operation of the ink ductor roller a predetermined number of times, when printing is stopped and an ink form roller (6-1 to 6-4) located at the end of an ink flow path of the ink roller group is thrown off, in a state in which the ink in the ink roller group has been decreased and in a state in which the opening amount of the ink fountain key (4-1 to 4-n) has been set to the corrected opening amount. decreasing ink in an ink roller group by scraping and removing the ink by an ink scraping member after an end of a print job including adjusting an amount of ink supplied from an ink fountain to an ink fountain roller by adjusting an opening amount of an ink fountain key (4-1 to 4-n) and supplying the ink supplied to the ink fountain roller to a printing plate via the ink roller group by a feed operation of an ink ductor roller; calculating the opening amount of the ink fountain key (4-1 to 4-n) corresponding to an image of a printing plate of a next print job; obtaining, as a correction value of the opening amount of the ink fountain key (4-1 to 4-n), a correction value according to an index value representing an ink supply amount corresponding to an image in an area of a printing plate of a preceding print job corresponding to the ink fountain key (4-1 to 4-n); correcting the calculated opening amount of the ink fountain key (4-1 to 4-n) corresponding to the image of the printing plate of the next print job with the obtained correction value of the opening amount of the ink fountain key (4-1 to 4-n); wherein the step of correcting with the correction value includes a step of adding the obtained correction value to the calculated opening amount; setting the opening amount of the ink fountain key (4-1 to 4-n) to the corrected opening amount; and forming, on the ink roller group, an ink film thickness distribution corresponding to the image of the printing plate of the next print job by performing the feed operation of the ink ductor roller a predetermined number of times, when printing is stopped and an ink form roller (6-1 to 6-4) located at the end of an ink flow path of the ink roller group is thrown off, in a state in which the ink in the ink roller group has been decreased and in a state in which the opening amount of the ink fountain key (4-1 to 4-n) has been set to the corrected opening amount.