To accurately read recording paper information previously recorded on a recording paper roll.

A long recording paper 11 is wound around a winding core and mounted in a printer as a recording paper roll. Recording paper information 51 is recorded at a plurality of positions scattered at an interval according to a sheet across a printable range on the reverse side of the recording paper 11. The recording paper information 51 is information showing the kind of the recording paper, the sensitivity of the recording paper, the date of manufacture and the like. The recording paper information 51 is read by an end detection sensor 37 to detect the side edge of the recording paper 11. Since the recording paper information 51 is printed on the reverse side of the recording paper 11, it is not liable to misread as in the case where it is printed on the end of the core and reading accuracy is improved. Since the information is recorded in a plurality of positions, the safety of information reading is secured.