To prevent an apparatus cost from increasing when a paper feed amount is corrected, and to always correctly obtain a correcting value to be used in an actual printing operation.

A printer prints a paper feed correction pattern 90 to an upper end of a paper P, and feeds the paper by an S(step) through an intermittent paper feed operation. At the same time, the printer prints the same pattern to a lower end as well. When a user sets the paper P again in the printer, the printer prints a reference line 93 to the upper end of the paper P, sends the paper by the S(step) through a continuous paper feed operation, and at the same time prints the reference line 93 also to the lower end. The printer calculates the paper feed correcting value based on paper feed correction information indicating which of a plurality of lines 91[n] arranged stepwise is traversed by the reference line 93 or to which of the lines the reference line is closest.