PURPOSE: To prevent the unnecessary increase and decrease in the tension of a ribbon accompanying the irregular rotation of a supply reel, by providing a supply reel driving belt cooperated with a ribbon feed roller.

CONSTITUTION: A ribbon 8 passes between a ribbon feed roller 3 and a pinch roller 7 from a supply reel 1 through a ribbon guide 5 and a printing head 6 to reach a take-up reel 2. A supply reel driving belt rotates with the rotation of the ribbon feed roller 3 to drive the ribbon wound over the supply reel 1. the ribbon 8 moves at a constant speed during by the rotation of the ribbon feed roller 3 but, at this time, the supply reel driving belt 4 also rotates at the same speed or at a linear speed slightly slower than said speed. Since the supply reel is driven by the supply reel driving belt, no excessive tension is applied to the ribbon and, since the supply reel is not rotated excessively by inertia when the feed of the ribbon is stopped, the ribbon is not slackened.