PURPOSE: To reduce troubles and time required for a transfer command of image data generated attended with check by selecting image data to be transferred from image data being an object of transfer based on a decoded result of additional information of image data and an image selection parameter.

CONSTITUTION: An additional information decoding section 2-1 decodes information required to select an image based on information added to the image and reads data from a parameter memory 2-2. Whether or not image data corresponding to the information added to image are relayed is discriminated by referencing an item corresponding to a content read from the parameter memory 2-2. Then image data are received from an A equipment 51 via an A equipment I/F 5 and stored in an image memory 4. Image data stored in the image memory 4 are converted matching a format of an H equipment 61. Then the image data are sent to the H equipment 61 via an H equipment I/F 6. Thus, the image is automatically selected and relayed by the medical use image gateway device 1.