PURPOSE: To enhance printing quality by preventing a booklet from being bent and tilted between roller parts in a time for printing the upper page and the lower page of the booklet and uniformizing the page surface to be printed so as not to be projected and recessed.

CONSTITUTION: The front-position conveyance roller part 2 and the rearposition conveyance roller part 3 have a set of a couple of rollers 4, 5 and are equipped in the front position and the rear position for conveying a printing head 1 which performs printing for a booklet S. A couple of rollers in the roller parts 2, 3 are changed over and moved to two positions of both the effective position for making conveyance of the booklet S effective by mutually pressing a couple of rollers and the ineffective position for making conveyance of the booklet S ineffective by mutually separating a couple of rollers. The front-position changeover part 10 and the rear-position changeover part 11 are provided to change over a couple of rollers in the roller parts 2, 3 to either of the effective position and the ineffective position in accordance with a changeover command. The booklet S is pulled by only either conveyance roller part in a time for printing the booklet S through changeover command sent from a controlling part 20 and conveyed.