A mechanism for performing tab paper printing and test printing by simple operation is provided. A printer performs a print process with an image formation position unshifted in the test printing and a print process with the image formation position shifted in the tab paper printing. In case of performing the tab paper printing after the test printing, the printing is performed by using print data already held in the printer or a host computer. It structured to enable to output to a plain paper a print result in which a decoration is added only to a tab position correspondence portion, enable to change its decoration method, and enable easy discrimination of the position. By the above structure, a user can easily correct the position of the content intended to be printed on a tab, and costs necessary for the tab paper used in the test can be reduced.