To efficiently execute assortment by handwork or automated assortment by a sorting means in a state that the sequence of pages is correct.

In the case when a copy having a front-side image 201 and a copy having a back-side image 202 are set in juxtaposition on a contact glass in this perfecting printing equipment, first the back-side image 202 is read and made into a plate, and after a prescribed space 204 is provided, the front-side image 201 is made into a plate, while the back-side image 202 is printed on the first printing paper and accommodated temporarily in a refeeding means. After the back-side image 202 is printed on the second printing paper, the front-side image 201 is printed on the other side of the first printing paper and delivered, and these operations are repeated. In the equipment thus constituted, the printing paper subjected to double-sided printing can be loaded with the front-side image 201 up.