1. A printing system including a printer for which particular information is set as a qualification designation and a host device for transmitting print information created by a particular application to the printer, wherein: the print information includes a print output instruction; the particular application has an information adding unit for appending added information corresponding to the particular information to the print information; the added information includes a decision instruction for deciding whether the print information includes the particular information, and a print/non-print instruction for allowing the print output instruction to be executed if the particular information has been set to the printer, and for causing the print output instruction to be replaced with a print disabling instruction and then executing the print disabling instruction if the particular information has not been set to the printer; and the printer comprises a decision unit configured to execute the decision instruction for deciding whether the print information transmitted from the host device includes the particular information; and a print processing unit that executes printing of the print information, wherein if the decision unit decides during execution of the print information that the print information includes the particular information, the print processing unit executes the print/non-print instruction, thereby enabling printing of the print information; and wherein if the decision unit decides during execution of the print information that the print information does not include the particular information, the print processing unit executes the print/non-print instruction, thereby disabling printing of the print information.