The Japanese researchers used sperm whales as guides to help them pinpoint likely giant squid haunts. Over the years whalers have reported finding a high number of large squid beaks in the mammals' stomachs, pegging sperm whales as primary predators of large squid.
The images are generating considerable excitement among squid experts.
"I think it's wonderful that we've finally got a picture of a living giant squid," said Richard Ellis, a research associate at the American Museum of Natural History in New York and author of The Search for the Giant Squid.
"I thought it would only be a matter of time before someone got images of Architeuthis," he added.
"After all, it's not an endangered species, not even all that rare, and it's one of the largest of all invertebrates. So the Japanese film finaly breaks through and renders the statement 'nobody has ever seen a living giant squid' inoperative."
Squid expert Martin Collins of the British Antarctic Survey based in Cambridge, England, says the new images are a "fantastic" achievement.
The marine biologist says he was skeptical that a dedicated giant squid hunt would succeed. He thought the first wild sighting would probably come by accident.
"Fair play to these guys who've made the effort, gone out there and looked in what they thought was a good area, and found it," he said.