To realize a compact printing machine with a favorable operability by a constitution wherein the respective impression cylinders of two kinds of printing units and the respective impression cylinders of printing units, which occupy before and after an obverse side printing part are directly connected to each other so as to produce respective two-color reverse side printing parts before and after the obverse side printing part.

The printing unit A of each obverse side printing part has an embodiment, in which a plate cylinder 1 contacts with two rubber cylinders 2 vertical upwards and the rubber cylinder 2 contact with an impression cylinder 3 vertically upwards. In a printing unit B, a paper feeding cylinder 7 connects with the impression cylinder 3 vertically upwards. The two rubber cylinders 2 contacting with this impression cylinder 3 and the plate cylinder 1 contacting with these rubber cylinders 2 are arranged operably from the front of a printing machine. In a printing unit C, a paper delivering mechanism 8 is connected with the impression cylinder 3 vertically upwards. The two rubber cylinders 2 contacting with this impression cylinder 3 and the plate cylinder 1 contacting with those rubber cylinders 2 are arranged operably from the rear of the printing machine. The impression cylinders of the these printing units B and C vertically and directly connect with the impression cylinders locating the front and the rear of the obverse side printing part 6. By means of the above-mentioned constitution, the respective two-color reverse side printing parts 9 and 10 are formed before and behind the obverse side printing part 6.