To provide a simple and convenient printing apparatus capable of realizing double printing, full color printing or double face printing by a simple composition and performing two color or four color printing or double face printing by easily lapping colors in a monochromatic machine or a dichromatic machine.

A re-feeding device 40 is provided feeding paper 39a already printed in one face from a re-feeding tray 44 to a printing part 13A again. A paper conveying device 5 has a pawl member 34 capable of holding a tip of printing paper 39 in times other than paper feeding and releasing a tip of the paper 39a already printed in one face in times other than paper delivery, a synchronous belt 33 fixed with the pawl member 34, and cams 55A and 55B driving release of the pawl member 34. It has a plurality of opening and closing portions for carrying out holding or releasing of the tip of the printing paper 3 or the paper 39a already printed in one face by the pawl member 34, and it is provided with a double printing conveyance and delivery means 49 for performing double printing and a double face printing conveyance and delivery means 112 for performing double face printing.