* Winning streak for Nikkei is longest since May-June 2015
* Kobe Steel resumes downtrend as US Justice Dept asks for records
TOKYO, Oct 18 (Reuters) - Japan's Nikkei share average rose for a 12th consecutive day on Wednesday, getting a lift from hopes that this weekend's election will produce political stability and continuation of loose monetary policy.
The Nikkei ended 0.1 percent higher at a fresh 21-year high of 21,363.05. It's the longest winning streak since May-June 2015, which was also 12 days, and equals the longest since Abenomics started in late 2012.
"Unlike Japan's lost decade era, the Nikkei has posted a long winning streak once in a few years lately. It means that something has changed, and that's corporate profits," said Takashi Ito, equity market strategist at Nomura Securities.
He said that Japanese companies' profits have been rising over the past few years and this fundamental factor is underpinning investors' risk appetite, on top of hopes that the ruling bloc will win Sunday's election.
The broader Topix was slightly higher, up 0.1 percent at 1,724.64.
Japanese Prime Minister Shinzo Abe's coalition is on track for a roughly two-thirds majority in the general election, a survey by Kyodo news agency showed, as its conservative rival led by Tokyo Governor Yuriko Koike appeared to lose momentum.
Japanese companies overwhelmingly want Abe's ruling coalition to stay in power but about two-thirds hope that it loses seats, according to a Reuters poll published on Wednesday.
Exporters were broadly steady on Wednesday, with Toyota Motor Corp up 0.7 percent and Hitachi Ltd climbing 0.9 percent.
Stock gains were capped by wariness over corporate scandals at some large firms.
Shares of Kobe Steel Ltd shed 3.1 percent, resuming their slide after rising in the previous session. The steelmaker's stock has dropped over 39 percent this month, since its scandal over data falsifying came to light.
Kobe Steel said Tuesday it has been asked by the U.S. Justice Department to submit documents related to its data fabrication, as the company delivers its products to a wide range of industries in the United States from car makers to airlines. (Reporting by Lisa Twaronite and Ayai Tomisawa; Editing by Richard Borsuk)