PURPOSE: To avoid the loosening and tensing of a thermal transfer ribbon by connecting a friction roller closely contacting with the peripheries of the winding side roll and sending-out side roll of the thermal transfer ribbon with a drive roller pressingly contacting with a printing medium on a platen.

CONSTITUTION: In printing, since a cassette 9a is moved under the condition that drive rollers 27 and 28 are pressed on a printing paper 2 on a platen 1, the drive rollers 27 and 28 are turned by friction with a printing paper 4. A belt 30 is run by the rotation of the rollers 27 and 28 to turn friction rollers 24 and 25, and thereby a sending-out reel 15 and a winding reel 16 are turned by the friction between the rollers 24 and 25 and the ribbon rollers 12a and 12b. The ribbon 12 is then rolled up by the winding reel 16. The ribbon 12 is sent out of the reel 15, and fresh ribbon face is supplied to the front face of the thermal head 8. Since the running speed of the belt 30 is constant, the peripheral speeds of the ribbons 12a and 12b become equal.