To provide a sheet-feed perfecting multicolor print offset printer having excellent printing performance and operability by constituting a cylinder array using five-cylinder type dichroic printing unit having small number of times of gripping a sheet by cylinder grippers, and always aligning rotating phases of plate cylinders of the front and rear printing sides.

Five-cylinder type dichroic printing units each having an impression cylinder 3 having a diameter of three times as large as diameters of a plate and a rubber cylinder are particularly set to one state that the respective rubber cylinders 2 are disposed in contact with above the impression cylinder and to the other state that the cylinders 2 are disposed in contact with under the impression cylinder. The cylinders 3 of the different states are horizontally aligned and alternately brought into contact with. At this time, axial centers of all the cylinders 1 are disposed on a vertical contact line of the impression cylinders, and the axial centers of the respective cylinders 2 are selectively disposed at suitable position between the impression and plate cylinders.