TOKYO -- The nation that filled the world with little automobiles has discovered something new: big, fast, luxury cars. But the latest consumer fad in Japan shows no signs of rescuing the American trade deficit.

Despite expensive gasoline, narrow streets and limited cruising space on these narrow islands, Japanese consumers with money to spend are breaking away from their habit of buying economical, if dull, cars. But instead of buying typically large American models, they are waiting six months or more to pay $70,000 for a BMW 735 or, increasingly, buying relatively large Japanese-made models such as Crowns and Cedrics, Centurys and Presidents.

The Japanese trend toward bigger cars has not really helped the prospects of American car sales here. In fact, sales of U.S. cars have plummeted during the past decade, with Ford Motor Co. -- number one among U.S. firms with 8,140 cars sold in 1975 -- selling barely 400 last year.

One BMW driver explained that big American cars have become associated in Japanese minds with yakuza -- the Japanese gangsters who, at least in the movies, like to be chauffeured in big, black U.S. sedans. More detrimental, though, has been U.S. car makers' relatively weak efforts to sell cars here and their image as producers of gas-guzzling, low-quality vehicles.

Japan is still not Los Angeles. Only two-thirds of households own an automobile, and fewer than 16 percent have two or more. Also, some Japanese models that seem large here would qualify as mid-sized cars in the United States.

In addition, although Japan is second only to the United States as an automobile market, only about 2 percent of the cars sold here are imported, far less than in any industrialized nation.

Still, Japanese consumers increasingly are buying cars for pleasure as well as convenience, and that has helped some foreign makers. Since 1980, as U.S. car sales declined, BMW sales increased almost fivefold; Mercedes-Benz sales more than tripled, and Saab, Volvo, Jaguar and Rolls-Royce also have risen.

"Five or 10 years ago, everybody here wanted to have the same thing," said Akio Seki, spokesman for BMW Japan Corp., the most successful foreign car maker here recently. "If one person had a Toshiba television, everyone wanted a Toshiba television. But now Japan is becoming more individualistic, more a consumer society like the United States or Europe -- and that goes for cars, especially."

"There's a lot of money around," Seki said. "Cars used to be just for transport. Now people would like to be different, they want luxury, they want comfort."

Many drivers also want status. Although the Japanese, like the British, drive on the lefthand side of the road with the steering wheel on the right, Seki said many customers prefer to buy cars with the steering wheel on the left. "A lot of people insist on lefthand side drive so that everyone can see, 'Oh, he's driving a foreign car,' " he said.

BMW sold 1,600 cars in 1975 and 15,000 last year, with 20,000 sales expected this year and 30,000 -- or about 1 percent of the Japanese market -- by about 1990. Despite U.S. troubles here, Seki predicted that the "trend to be different" eventually will aid U.S. automakers, too.

Ford Motor Co. (Japan) executive Kenji Kawai also predicted that U.S. sales will pick up. He said sales dropped because the high dollar until recently made American car prices "horrendously high," U.S. companies didn't try as hard as some European firms and because Ford "hadn't quite caught up with world-level quality."

"All that compounded, people just stopped buying American cars," Kawai said.

But Kawai said he believes that the trend will reverse itself, in part because a cheaper dollar has made U.S. products less expensive here and in part because Ford quality and design have improved. "We believe the American car will begin to capture the fancy of the Japanese public again," he said.

In the meantime, Japanese automakers, who are capturing a larger share of the expensive car market in the United States, also are selling a greater variety of cars in Japan. The number of cars in use with engines of more than 2,000-cc capacity has increased fivefold in a decade, while the percent of cars sold with automatic transmission increased from 34 percent to 57 percent in five years.