A printing apparatus and a printing registration method permits printing registration between a forward and a reverse scan of a head cartridge between a plurality of head cartridges without troubling a user and simply. By forward and reverse scan of the head cartridge, a plurality of patterns, in which a print start timing of the reverse scan is shifted per a predetermined amount relative to that of the forward scan, are printed. These patterns may vary an area factor by the dots formed by printing depending upon offset amount. On the other hand, the plurality of patterns are optically read an average density. By this, the timing, at which the read average density is maximum is set as the printing registration condition.