An image forming apparatus includes an image input device that reads an image to obtain image data and a printer engine that forms an image on a medium based on image data. A bus of a PCI Express standard is used to transfer data. Storage areas serving as end points of the standard and hardware resources that transmit data and receive image data to and from the storage areas are connected to an identical switch according to the PCI Express standard. Specifically, an input/output area, an image input device, and a printer engine are connected to one switch, and a storage area, a compressor, and a hard disk is connected to another switch.