The captured image acquisition unit 52 acquires the data of the subject focusing image P1 and the non-subject focusing image P2 with different focal points. The image depth map generation unit 91 generates the subject depth map DMP1 and the non-subject depth map DMP2 that represent a distance relationship of a subject in an image for every pixel for each of the subject focusing image P1 and the non-subject focusing image P2 acquired. The composition depth map generation unit 92 performs predetermined processing on the subject depth map DMP1 and the non-subject depth map DMP2 thus generated to generate the composition depth map DMP3. The image composition unit 55 composites the data of the subject focusing image P1 with the data of the non-subject focusing image P2 based on the composition depth map DMP3 thus generated to generate the data of the omnifocal image P3.