An ink supply method in an ink supply apparatus including an ink fountain, a plurality of ink fountain keys, an ink fountain roller, an ink ductor roller, and an ink roller group. An ink film thickness distribution corresponding to an image on a printing plate is formed in the ink roller group. The ink roller group is divided into a plurality of roller subgroups. After or before division, a throw-on operation is performed for at least one of the plurality of roller subgroups, and a plate cylinder on which the printing plate to be used for printing of the next job is mounted. Ink in at least one of the plurality of roller subgroups is supplied to the printing plate mounted on the plate cylinder by rotating the plate cylinder and at least one of the plurality of roller subgroups. An ink supply apparatus is also disclosed.