An object of the present invention is to provide an edge detection technique and equipment which are capable of stably detecting an edge by suppressing the influence of noise even in the case where the image is obtained by charged particle radiation equipment, such as a scanning electron microscope and has a low S/N ratio. More specifically, the present invention is to propose a technique and equipment which are configured to determine a peak position (edge) on the basis of the following two edge extraction techniques. That is, the present invention is to propose a technique and equipment wherein at least two peaks are formed by using, as edge detection techniques, for example, one peak detection technique having a relatively high sensitivity and the other peak detection technique which is relatively less susceptible to the influence of noise than the one peak detection technique, and wherein a position where the peaks coincide with each other is determined as a true peak position (edge position).