To realize precise measurement of CTF in CTF measurement using a chart method by using a chart that a Nyquist frequency is the prescribed frequency and a frequency part whose drop rate of amplitude owing to the irregularity of the phase of sampling becomes not less than a specified value is not contained, as a rectangular wave chart.

A high definition evaluation device receives an accumulative fluorescent substance sheet 20 where a rectangular wave chart is exposed by a digital radiography device and CTF is calculated from light emitting strength data on the fluorescent substance sheet 20. In calculating CTF, a value corresponding to a frequency exceeding the Nyquist frequency of a pattern on the rectangular wave chart is not used. A value (data) corresponding to a spatial frequency applied to a frequency which is one over the integer of the Nyquist frequency and a frequency whose drop rate of amplitude due to the phase shift of sampling becomes not less than 10% is not used.