The roll paper loading mechanism of a roll paper printer has a left side panel rendered in unison with a roll paper holder. The roll paper holder pivots to the front of the printer in conjunction with the operation opening an access cover. When the access cover is opened completely, the left side panel protrudes through an opening formed in the printer case to the front of the printer. A right side panel disposed to hold the roll paper between it and the left side panel is stationary inside the printer case. A roll paper guide tab that projects to the front of the printer and extends away from the left side panel is formed on the front end of the right side panel.