To provide a method for coloring the top edge, the bottom and the fore edge of a booklet which makes it possible to efficiently color only the top edge, the bottom and the fore edge without coloring the back.

When a large number of booklets B reaches inside a main body 1404 by conveyance along an upper conveyance route 6, dye is blown against the top edge T and the bottom C of the booklet B from nozzles 16A and against the fore edge K of the booklet B from a nozzle 16B, and thereby the top edge T, the bottom C and the fore edge K of the booklet B are colored. Since air from air nozzles 20 is jetted in the extended direction of the direction of extension of the back S from the opposite ends of the direction of extension of the back S on the occasion, the dye blown from the nozzles 16A and 16B does not penetrate into the back S and only the top edge T, the bottom C and the fore edge K of the booklet B are colored.