An image-processing device configured to process image data including at least one face image includes an image-input unit configured to input the image data, a face-detection unit configured to detect the at least one face image from an image frame of the input image data, an importance-determination unit configured to determine importance of each of the at least one detected face image, and a priority-determination unit configured to determine priority of each of the at least one detected face image based on the determined importance. The importance-determination unit determines the importance considering data on the size and position of the detected face image shown in the image frame, and a priority determined by the last time by the priority-determination unit.