An ink ribbon cassette has a box-shaped ribbon container for housing an endless ink ribbon and a ribbon protector positioned between a sheet of print paper and the ink ribbon exposed between ribbon guide arms. The ribbon protector is elongate in shape and has a pair of holes defined in the opposite ends thereof and a central hole. The ribbon protector is mounted in position by fitting the end holes thereof over projections on the ribbon guide arms. The ink ribbon cassette also has a pair of holders for preventing the mounted ribbon protector from being detached from the ribbon guide arms. During a printing operation, the ink ribbon is pressed against the sheet by a print head through the central hole in the ribbon protector.
