To solve a problem that a contact means impregnated with a treatment liquid to contact with an ink ribbon for making a recording mark left on the ink ribbon unreadable cannot meet a large shape change of a winding diameter of a used ink ribbon in a thermal transfer printer which performs print by thermally transferring the ink ribbon to a recording paper.

The contact means impregnated with the treatment liquid is brought into contact with a winding surface of the ink ribbon by contact pressure by its own weight of the contact means including the weight of the treatment liquid, thereby making the recording mark of the ink ribbon unreadable.