PURPOSE: To provide a means adaptable to the device of a present technique in which a desired result can be attained by a simple and effective method without enforcing the beauty and functionality of a substrate to be printed.

CONSTITUTION: A method for evaluating a printing quality on a substrate 15 is constituted of a process for plotting and printing the picture of a small inconspicuous second-dimensional element body 16 in the inconspicuous blank part of the substrate 15 by a printer 11 (a), process for optically scanning the second- dimensional element body 16 on the substrate for obtaining the electronic data of the quality of the plotting and printing of the picture of the second- dimensional element body 16 (b), and process for electronically comparing and analyzing the electronic data obtained in the previous process with the allowable reference of a plurality of factors for deciding the printing quality (C).