An image forming apparatus, connected to an information processing device via a network, includes a receiving section, a memory, an interpretation section, and a transmission section. The receiving section receives a plurality of pieces of print data from the information processing device via the network. The plurality of pieces of print data include first print data for normal printing, second print data for interruption printing, and third print data. The memory has first to third buffers. The first and second buffers store the first and second print data, respectively. The third buffer stores the third print data during execution of the interruption printing of the second print data. The interpretation section interprets the plurality of pieces of print data. The transmission section transmits a reply message to the information processing device in accordance with a result of the third print data interpreted by the interpretation section.