TOKYO (AP) _ The main index on the Tokyo Stock Exchange bounced back today for its first gain this week, while the dollar moved higher against the yen.

The Nikkei Stock Average of 225 selected issues, which lost 963.85 points Thursday, gained 528.82 points, or 1.77 percent, to close the week at 30,372.16.

The leading index had fallen 2,773.1 points during the three previous trading days this week. The stock market was closed Wednesday because of a national holiday.

Volume on the market's first section was estimated at 600 million shares, up from 580 million shares on Thursday.

The Nikkei index fell in early morning trading because of profit-taking by institutional investors, securities dealers said.

But the index rose sharply toward end of the day, with stock futures being bought back, in part because of a series of buy orders by arbitrageurs, they said. Arbitrageurs profit from price differentials between the futures and spot markets.

''The market is slowly but gradually recovering, helped by relative stability in the currency and bond markets,'' said Akira Shimoda, an equity analyst with Yamaichi Securities.

Shomoda said the Finance Ministry's approval Thursday of a measure that allows Japan's four major brokerage houses to handle more than 30 percent of the purchase orders of any particular stock in a month would ''greatly help'' activities at the securites firms and strengthen the market.

Japan's four major securities firms - Nomura Securitiies, Daiwa Securities, Nikko Securities and Yamaichi Securities - had asked the Finance Ministry to ease the restriction, a rule set up to check insider trading, he said.

The four securities firms account for about half of the market's total turnover, a market analyst said.

In the foreign currency market, the dollar closed the week at 155.07 yen, up 0.24 yen from Thursday's close of 154.83 yen. After opening at 154.75 yen, the U.S. currency ranged between 154.65 yen and 155.25 yen.

''The demand for the dollar basically remains strong,'' said Toshio Takahashi, a dealer with the Industrial Bank of Japan. ''The American economy is good, despite cautiousness over inflation'' among U.S. monetary authorities, he said.

Finance Minister Ryutaro Hashimoto was to leave later today for a weekend meeting focusing on exchange-rate movements with Treasury Secretary Nicholas Brady in Los Angeles.

Hashimoto told a parliamentary budget committee session today that he will seek U.S. cooperation in keeping currencies stable within the framework of policy coordination among the Group of Seven major industrialized countries.

The price of benchmark No. 119 Japanese government bonds closed at 86.97, up from Thursday's 86.54. The yield fell to 7.145 percent from 7.235 percent the previous day.