To solve the problem that there exist an optical limit using a telecentric optical system and a limit in terms of throughput that processing for restoring a deteriorated image is performed twice or more times.

The image photographing device includes: an observation image photographing part 221 which obtains a plurality of observation images by photographing the same object in a plurality of diaphragm patterns; a calculation part 222 which calculates optical transmission characteristic in accordance with a distance to the object; and a distance arithmetic calculation part 206 which calculates the distance to the subject from the plurality of observation images and the optical transmission characteristic. The image taking device includes an observation image taking part 221 which obtains a plurality of observation images by photographing the same object in a plurality of diaphragm patterns; a calculation part 222 which calculates optical transmission characteristic in accordance with a distance to the object; an optical transmission characteristic arithmetic calculation part 206 which calculates optical transmission characteristic that a blur amount is minimum from the plurality of observation images and the optical transmission characteristic, and a blur restoring part 207 which obtains a focused image by restoring the blur of the image by the use of the optical transmission characteristic that the blur amount is minimum.