A method that enables a multiple-port print device to perform efficient job management for each job even if the multiple-port print device is provided with parallel-processing-enabled multiple interfaces. The multiple-port print device includes a job boundary detection unit, a spool buffer, and a job management unit. By reading print job data stored in the buffer memory units from the multiple communication interfaces, and detecting the job start and end marks added to the print job data, the print job data is identified by each job boundary. The job management unit stores the print job data identified by the job boundary into the spool buffer as a spool file to spool-process the data between the spool buffer and the image processing unit.