To solve the problem that when printing including confidential contents is interrupted, the printing contents can be seen from the outside between printing apparatuses in a double-sided printing system for the continuous paper having a continuous configuration.

When the indication to interrupt the printing to continuous paper is issued, it is judged whether there is printing which needs secret maintenance on a handling sheet located between a printing apparatus 130 and a printing apparatus 140. When the printing which needs secret maintenance exists between apparatuses, a blank paper page is inserted until the printing of the secret contents hides in the printing apparatus 140 from printing apparatus 130 side. Moreover, when the printing which does not need secret maintenance exists between apparatuses, the printing is then interrupted. In the way, the disclosure of the secret contents and useless consumption of paper can be suppressed.