TOKYO, Dec. 17-- Japan's major opposition Democratic Party will hold an election on Thursday to pick a successor to outgoing leader Banri Kaieda, it is reported Wednesday.

Goshi Hosono, a 43-year-old former nuclear disaster minister, will run for the top job in the party, Kyodo News Agency citing party sources as saying.

His contenders include the party's current acting president Katsuya Okada, former party leader Seiji Maehara and Secretary-General Yukio Edano.

In Sunday's parliamentary elections, the Democrats gained more seats in the Diet, but party leader Kaieda himself failed to secure a seat.

Kaieda announced his resignation on Monday.