To make management for an underwater photograph and a photographed image thereof utilized easily in a diving log, prepare the diving log in a site, and facilitate management for the diving log.

A log printer 4 finds a depth of water and a water temperature according to a start time + a lapse of time of diving while referring to a diving data from a diving computer 2, and prepares a diving profile for showing changes of the depth of water and the water temperature along with the diving lapse time. The printer 4 also prepares the diving log using an image data from a digital camera 1, the diving profile, a weather and an ambient temperature from an input part 5, and the like, and prints it by a printing part 8. A diver receives a sign in handwriting by a guide or a buddy (companion) on the diving log in the site after the diving is finished, as an evidence for an actual result of the diving.