To perform a monochromatic printing without waiting for the replacement of a toner cartridge when the toner in the toner cartridge mounted on a printer breaks off.

In a printing method by which the printer obtaining a printing data from a host computer performs chromatic printing based on the printing data, transmission steps (S101 and S102) to transmit information that the toner in one toner cartridge out of several toner cartridges mounted on the printer breaks off to the host computer and printing steps (S104 and S105) to perform the monochromatic printing in accordance with printing instruction information from the host computer which receives the information are provided.