<；P>；PROBLEM TO BE SOLVED: To efficiently improve the accuracy of the unknown obtained under a condition in which the value of measuring factors is limited in the measurement to find the unknown included in a function from a plurality of measured values obtained by a plurality of times of measurement with different measuring factors when a signal obtained from a subject for examination is expressed as a function with a measuring factor as a variable. <；P>；SOLUTION: The condition for limiting the measuring factors is received, and under the condition, a set of measuring factors to minimize the difference between the initial value of an unknown parameter included in the function and the value of parameter obtained from the calculation assuming that a certain error is included in the measured value are calculated. The measurement is executed using the obtained set of measuring factors, and the parameter is calculated from the obtained measurement data. <；P>；COPYRIGHT: (C)2010,JPO&INPIT
