1. A device for cutting out a moving image, the device 5 comprising: sampling means for sampling a plurality of sequential frames from the moving image including a moving body; mask frame calculating means for calculating mask frames, which include mask regions for identifying positions of the moving body in the plurality of frames, corresponding to each of the plurality of frames; region cutout means for cutting out at least one moving body region corresponding to the moving body from all or part of the plurality of frames by masking all or part of the plurality of frames using the mask frames which correspond thereto; and display means for displaying the at least one moving body region cut out by the region cutout means, wherein the mask frame calculating means includes: first mask frame calculating means for calculating other mask frames, which includes the mask regions for identifying the positions of the moving body in other frames, corresponding to each of the other frames by calculating the absolute values of difference values in corresponding pixels between a reference frame selected from the plurality of frames and the other frames and by binarizing the absolute values based on a first threshold; and second mask frame calculating means for calculating a reference mask frame, which includes a mask region for identifying a position of the moving body in the reference frame, based on information on the plurality of other mask frames, and wherein the region cutout means includes a means for cutting out a moving body region corresponding to the moving body from the reference frame by masking the reference.