Provided is an image processing apparatus and an image processing program which are capable of selectively and readily acquiring a geometrical physical quantity of a desired measuring portion. An object image is displayed based on object image data, and a measuring portion designating image corresponding to a specific portion of the object image is displayed based on designating image data. By operation of an operation part by a user, the displayed measuring portion designating image is moved relatively to the object image. When the measuring portion designating image is moved to a specific portion of the object image, a geometrical physical quantity of a measuring portion of the measuring object, previously set so as to correspond to that specific portion, is measured.