In a label printer, a top cover made of transparent resin is attached to a
housing at a rear upper edge to cover a roll sheet holder storage part
and to be freely opened and closed. A roll sheet of a roll sheet holder
removably mounted in the roll sheet holder storage part is visible
through the transparent resinous top cover. The roll sheet is provided
with a plurality of medium information marks by printing. The medium
information marks are visible through the top cover.