PURPOSE: To enable printing irrespective of the thickness of a body to be printed by a method wherein the interval between an upside roller and an underside roller can be adjusted by turning a screw rod.

CONSTITUTION: Near an underside roller 5 in a frame 1, a supporting frame 12 equipped with an internal thread 10, to which a screw rod 11 equipped with an external thread is screwed, is disposed upright. By turning the screw rod 11, the screw rod 11 is moved vertically. Into the supporting frame 2, a lifting body 15 is slidingly fitted vertically and movably under the condition that the lower end of the screw rod 11 is connected with the lifting body 15. Or, by turning the screw rod 11, the lifting body 15 moves vertically. To the lifting body 15, a cam 17 is mounted rotatably. To the frame 1, a tilting plate 19 is tilted, resulting in moving the underside roller 5 vertically. Thus, the interval between the underside roller 5 and an upside roller 3 can be adjusted.