PURPOSE: To always suitably hold an interval between a platen and a card holder by providing the holder in a direction perpendicular to the platen capably of reciprocating, and providing a spring mechanism for always pressing to the platen side on a carriage.

CONSTITUTION: When a printing is conducted by a printing head 52, a platen 50 is rotatably driven by an external force, a printing sheet 51 is conveyed between pressure rollers, guided by a card holder 2, and supplied to a position opposed to the head 52. A coil spring 4 is provided along the second protrusion 10B of the holder 2 between the holder 2 and a carriage 1, and two bearing balls 3 provided at the holder 2 press the sheet 51 to the platen 50. As a result, the interval between the platen and the holder can be always suitably held irrespective of variation in the thickness of the sheet without regulating at the time of manufacture.