At least eight people died and 46 were missing as of Saturday after days of record rainfall and flooding in western Japan, Sputnik reported citing local media.
Five deaths were recorded in the Hiroshima prefecture where rains caused rivers to burst their banks and triggered landslides, NHK reported.
In the Hyogo prefecture, a 59-year-old man was reportedly swept away by rainwater while cleaning pipes. In the Osaka prefecture, a 52-year-old drowned in the river.
Japanese cabinet spokesman Yoshihide Suge told reporters after an emergency morning meeting chaired by Prime Minister Shinzo Abe that large-scale rescue operations were underway, involving almost 50,000 police, firefighters and troops.
Japanese authorities have reportedly warned that heavy rainfalls brought by Typhoon Prapiroon could trigger dangerous mudslides.
A total of 26,000 were advised to evacuate throughout Osaka after the storm made landfall in the country's southwest.
More than 100,000 people living in Kobe on Osaka Bay in central Japan were urged to prepare for evacuation. The measure was also recommended to 14,000 people in the Kyoto prefecture and 27,000 in Hyogo.