At least 18 deaths were confirmed from Typhoon Wipha and 45 people are missing, the government said.
Hardest hit from the storm, which swept up Japan's eastern coast yesterday, was Izu Oshima island, about 120 km south of Tokyo.
Some 1,100 rescuers were searching through mountains of trees, wrecked homes and other debris, shouting in hopes of finding survivors. Residents and shop owners cleaned out the mud from their buildings.
Katsunobu Kato, a government spokesman, told reporters that his understanding is that proper warnings were issued regarding forecasts for torrential rains.
The areas affected by the mudslides were indicated as hazardous zones on maps, he said, adding that the government was checking to see if there was any factual basis for complaints that an evacuation order should have been issued.
More than 350 homes were damaged or destroyed, including 283 on Izu Oshima, the Fire and Disaster Management Agency said.
More than 30 inches of rain fell on Izu Oshima during a 24-hour period ending last morning, the most since record-keeping began in 1991.
Izu Oshima is the largest island in the Izu chain southwest of Tokyo. It has one of Japan's most active volcanoes, Mount Mihara, and is a major base for growing camellias. About 8,200 people live on the island, which is accessible by ferry from Tokyo.
