Adventure World, where the giant panda lives, said Rauhin the giant panda gave birth to a female and male cub and has already started nursing the healthy infants, The Yomiuri Shimbun said Thursday.
While the newborns bring the total number of cubs born at the Japanese tourist site to 10, they represent the first time a giant panda born in Japan has successfully given birth.
Rauhin was born at Adventure World in 2000 and began mating with a Chinese panda this April, the newspaper said.
The Mainichi Shimbun said the births bring the total number of Adventure World giant pandas to eight -- the largest giant panda population at any single site outside China.
The Daily Telegraph said giant pandas are becoming increasingly endangered in the wild because of increased development in China. The World Wildlife Fund estimates only 1,600 giant pandas are thought to be living in the wild.