PURPOSE: To enable positioning of a printing paper to be achieved at a stroke simply by setting the paper onto a tractor through matching an edge to a guide piece, by providing a plurality of guide pieces capable of being moved to arbitrary positions on a guide rod disposed horizontally over the printing paper, and providing each of the guide pieces with a marking corresponding to the position of the paper.

CONSTITUTION: A printing paper 1 is wrapped on a platen 6, and is set to tractors 4, 4. A guide rod 2 is stretched over the paper 1, and a number of guide pieces 3 provided with markings as shown are provided on the rod 3. The guide piece 3 is located at such a position at which an edge of the printing paper 1 used coincides with the position of the marking. When a number of different printing papers 1 are used, the guide pieces 3 are disposed at different positions on the guide rod in conformity to the edges of the printing papers to be positioned.