An ink jet printing apparatus and an ink jet printing method according to the present invention suppress a variation in the density of ink in a supply channel and a print head without the need for useless recovery operations, thus always providing very reliable high-grade images. The ink jet printing apparatus carries out printing using a print head for ejecting ink. The apparatus includes a scanning unit for causing the print head to scan across a printing medium, a measuring unit for measuring a time from an end of a preceding printing operation until a start of a current printing operation, and a determining unit for determining whether or not a result of measurement executed by the measuring unit exceeds a predetermined value. The scanning unit causes the print head to carry out at least one idle scan before the start of a printing operation depending on a result of determination made by the determining unit.