The present invention provides a spooler that adequately manages and controls print jobs, which require establishment of mutual communication, with relieved loading. In the arrangement of the present invention, a buffer is provided corresponding to each printer PRT connected to a network LAN to successively spool print jobs transferred from clients. In the case of a conventional print job, a print queue and whole print data are spooled in the buffer. In the case of an interactive print job that requires mutual communication between the client and the printer, only the print queue is stored in the buffer, while a wait signal is output to the client to wait for transmission of the print data of the print job. In order to carry out the interactive print job, printing is executed via a bypass that establishes the mutual communication not via the buffer but directly between a print job execution unit and the client.