PURPOSE: To prevent an image from being erased and to hold the image at hand for a required period without storing and saving the image in an external auxiliary memory device when a required image is present.

CONSTITUTION: This method is comprised of a selection means 101 to select the image of an arbitrary patient required and desired to hold, a storage means 102 to store the image attribute information of a selected image, an information setting means 103 to attach newly information representing the fact that the selected image is set in an erasure inhibited state, an information erasing means 104 to cancel the erasure inhibited state of an unrequired image, and a display means 105 to display whose patient or which image is set in the erasure inhibited state.