An image processing device sets a determination target area based on a pixel to a taken image for each of a plurality of pixels included in a pixel group obtained as a candidate of a nucleus of a target cell, and determines whether or not the target cell is included in the determination target area, which is set by the setting section for each of the plurality of pixels included in the pixel group, based on whether or not an image feature amount obtained from the determination target area satisfies a condition of the image feature amount of the target cell.