PURPOSE: To perform high speed continuous gradation printing generating no color mixture to the outer surface of a cylindrical container, by respectively preparing inks having colors of the same color phase system obtained by color separation and forming a protruded part to each plate at every same color phase system and performing continuous printing by a dry offset press.

CONSTITUTION: The color of the fruits part of a design, for example, having an orange color desired to be applied to the outer surface of a can body X is separated into yellow, orange and dark orange of the same color phase system imparting no effect to inks even when said inks are mixed and the plates 48, 4C, 4D corresponding to the respective colors are prepared. A green plate 4A is added to set the plates 4AW4D to the corresponding plate cylinders 3A 3D and the inks (g), (y), (o), (d) corresponding to the colors are supplied to ink distributing rollers 2AW2D. When a printing press P is operated, the inks of the respective colors applied to the protruded parts 4aW4d of the plates are successively transferred to the same blankets 6AW6D provided to a transfer roll 5 and, at the point of time when the transfer roll 5 passes the last plate cylinder 3D, all of the color inks are transferred to one blanket cylinder D.