A data processing apparatus includes an image reader for reading an original, a receiver capable of receiving an external job transmitted from an outside, a transmitter capable of transmitting image data of the original read by the image reader as a scanning job to an outside, a print device for printing data of the external job received by the receiver, one or a plurality of compressing/expanding devices for compressing the image data of the scanning job or the data of the external job and expanding the compressed data, and a controller. The controller controls execution of processing of the external job and the scanning job by the compressing/expanding devices in accordance with execution status of the external job in cases where a request for processing the data of the external job by the compressing/expanding devices and a request for processing the data of the scanning job by the compressing/expanding devices overlap.