1. A method for modifying a standard model based on measured data, comprising the steps of: modifying the standard model prepared in advance of modification in accordance with the measured data and deciding whether to further modify the standard model or to finish the modification of the standard model based on integrated evaluation of two or more functions selected from a first function relating to a distance between the standard model and the measured data, a second function relating to a distance between a characteristic point defined on the standard model and a characteristic point specified on the measured data and corresponding to the characteristic point defined on the standard model and a third function relating to a distance between an outline defined on the standard model and an outline specified on the measured data and corresponding to the outline on the standard model.