To reduce paper jamming in a printer when roll paper is automatically loaded.

There is provided a printer which automatically loads roll paper P, prints, and discharges the paper and in which first and second sensors 33, 34 for detecting a thickness of the roll paper are arranged in a roll paper conveyance path at an interval in a width direction of the roll paper P. When the rolled paper P has a folded-back part at its front edge and the first and second sensors 33, 34 detect the thickness of the roll paper being as large as two or one sheet, the roll paper P is cut in a direction orthogonal to the conveyance direction using a cutter 35 after being conveyed by a certain quantity; and then the loading is restarted and printing is carried out.