a printer having a printing unit for printing on a sheet and a sheet feeding control section for controlling continuous or cut sheet feeding is disclosed . the sheet feeding control section performs sheet feeding of a predetermined amount after the data corresponding to one page has been printed by the printing unit . the sheet detecting section detects whether or not the printing sheet exists in the vicinity of the printing unit . if no printing sheet is det4ected in the vicinity of the printing unit , the printing control section determines that no continuous - page sheet feeder has been mounted . on the other hand , if the printing sheet is detected , the printing control section determines that the continuous - page sheet feeder has been mounted . if it is found that no continuous - page sheet feeder is mounted , the printing operation is stopped temporarily . if it is found that the continuous - page sheet feeder has been mounted , the printing operation is continued .