The video -- taken from the hiker's point of view -- shows what appears to be a scene near the top of Japan's iconic mountain, above the clouds. The ground is covered in heavy snow, and the man tells his viewers that it is slippery and dangerous along the route.
"Am I on the right track? So much of the route is covered with snow," he says as he climbs upward.
"I'm slipping," the man shouts, as he then appears to fall.
Authorities were alerted to the incident after receiving calls from people watching the live stream of the climb up the mountain, Aiko Kishibata, a press officer with Shizuoka prefectural police, told CNN earlier Wednesday.
Rescue workers from Shizuoka and Yamanashi, the two prefectures that Mount Fuji straddles, have been searching for the climber since early Tuesday morning, she added.
Officials found a body Wednesday afternoon, and are working to identify it, said Masahiro Haruta, a spokesman for the Shizuoka Prefectural Police. The body was found at an altitude of around 3,000 meters (9,800 feet). Haruta said it was too early to say if the person who died was in fact the live-streamer.