In a case of printing documents having a plurality of pages (documents number c) on output sheets so as not to exceed a limited output sheets number a, the limited output sheets number a and an output copies number b are set (S1 and S2), and the documents number c is confirmed in reading the documents (S4). When the limited output sheets number a, the output copies number b, and the documents number c are recognized, a print document pages number d which is a number of original images that should be printed on each output sheet is set in accordance with the foregoing values (S5). When the print document pages number d is set, an output mode which allows the documents to be printed in accordance with the print document pages number d is set (S6), so that a printing operation is carried out (S7). Further, in S1, each of allowable amounts of sheets stored in (i) sheet feeding means, (ii) delivery means, and (iii) post-processing means may be recognized as the limited output sheets number a. Thus, in a case of outputting image data corresponding to the plural pages on the output sheets so as not to exceed the output sheets number less than the number of document pages, it is possible to reduce operations that the user has to perform in setting a printing condition.