Kyushu Electric Power Company says about 464,000 households in the Kyushu region were without power as of 4 a.m. on Monday.
The utility says work to restore power will begin as soon as possible after the storm passes. Officials are urging residents to stay away from downed power lines.
The Japanese government has started delivering cloth masks to every household in the country in a bid to deal with the shortage amid the coronavirus outbreak.
Post office workers began delivering packages containing two washable masks to homes in Tokyo's Setagaya Ward on Friday morning.