To supply an image obtained by an image diagnosing device to a computer network by receiving the image from the image diagnosing device, converting the received image into image data of a prescribed format and outputting the converted image data to the computer network.

A CPU 1 converts a format of image data from a modality (image diagnosing device) 20 received via a modality interface 5 into a prescribed format and the resulting data are stored on a hard disk HD 7. The image data stored in the HD 7 are sent to computers 23, 24, an image output device 21 connecting to an imager 22, or a DICOM printer 26 having an interface corresponding to a DICOM protocol via a network interface 8 and a network 25 such as an Ethernet by the CPU 1. Thus, the diagnosed image data are easily outputted to the computer system in the DICOM format.