Alpinist Yasushi Yamanoi was seriously injured Wednesday by a bear while jogging in the mountains near his home in western Tokyo, police said.
The 43-year-old climber, who has scaled the Himalayas and other peaks, sustained face and arm injuries before fleeing to a nearby home in Okutama.
The homeowner called an ambulance at around 7:30 a.m.
The two bears involved in the incident near the Yamanashi Prefecture border were thought to be a mother and cub, police said.
The Environment Ministry said bear attacks are rare in Tokyo. The most recent, in 2006, was the only attack recorded since 2004.