* Nikkei's winning streak longest in 27 years * Fuji Heavy hits record high on weak yen, U.S. econ optimism By Ayai Tomisawa TOKYO, May 28 (Reuters) - Japan's Nikkei share average rose on Thursday morning, extending its gains to a 10th day as investors hoped exporters' earnings will rise after the dollar hit eight-year highs against the yen.

The Nikkei 225 rose 0.7 percent to 20,620.59 in midmorning trade after climbing as high as 20,632.31, the highest since April 2000. If it manages to trade above 20,833.21, it will be the highest since June 1997.

The index has risen for 10 consecutive days, the longest winning streak since February 1988, surging 5.2 percent.

The dollar hit an eight-year peak of 124.09 yen on expectations the Federal Reserve would raise interest rates later this year as more indicators show the U.S. economy is recovering from an anaemic first quarter.

"I thought the market would see a correction given the straight days of gains, but contrary to my initial view, it's being lifted by the weak yen," said Masashi Oda, chief investment officer at Sumitomo Mitsui Trust Bank. "The market had been numb to the dollar-yen moves when the dollar was trading in a fixed range with an upside of around 121-122 yen, but now that people are expecting a higher range, the market is reacting to it positively." Automakers were in demand, with Toyota Motor Corp rising 1.5 percent, Honda Motor Co adding 2.1 percent and Nissan Motor Co gaining 1.6 percent.

Fuji Heavy Industries soared 2.9 percent to a record high of 4,827.5 yen as it sells more than half of its cars in the United States, many of them exported from Japan.

Traders said strength in the U.S. economy helped power the maker of Subaru cars - on top of the weakening yen.

Ain Pharmaciez soared 12 percent to an 1-1/2-month high of 4,990 yen after the drugstore chain said it expects a 17 percent increase in its operating profit to 13.4 billion Japanese yen ($108.23 million) for the year through April 2016, and plans to pay 40 yen per share for dividends, up from 30 yen per share.

The broader Topix gained 0.8 percent to 1,675.26 and the JPX-Nikkei Index 400 rose 0.8 percent to 15,140.57.

($1 = 123.8100 yen) (Editing by Eric Meijer)