A printer can print to paper with a narrow width while maintaining a print format with good legibility without changing the application program and printer driver installed on the host computer. The control method of a printer that prints based on print data 5 sent from a host computer 3 has a step S105 of extracting data attributes contained in the print data 5 and assigning the print data 5 to data segment areas for each data attribute; a step of setting the data segment areas to specific printing areas based on the data attribute; an actual print data generating step (steps S122, S107, S133, S134, S111) of converting the print data 5 assigned to the data segment areas to actual print data according to the data attributes; and a printing step S113 of printing the actual print data in the printing areas.