Mikhail S. Gorbachev on Wednesday made his bluntest public appeal yet for foreign aid, telling Parliament that Japan and other advanced countries must prevent the Soviet Union from collapsing and returning to dictatorship.

"If we don't halt the disintegration of the state - of the economy, the law and relations between republics - the country could fall into the chaos that gives birth to dictatorship," the Soviet president said."Despair and hopelessness are a serious threat to the progress of civilization. Therefore, advanced countries help themselves by helping others," the first Soviet leader to visit Japan said in his address.

Gorbachev urged resource-poor Japan to help mine his country's vast mineral deposits. "Our Far East and Siberia have resources, but they lack the infrastructure to develop them," Gorbachev said. "I appeal to Japanese companies to consider helping develop the region."

Gorbachev had entered the Diet, or Parliament, smiling, his wife, Raisa, at his side. He received standing ovations at the beginning and end of his 45-minute speech, which was interrupted seven times by applause.

The Soviet leader said his country was making further military reductions in the Far East. He also proposed a regional security conference that would include the United States, Japan and the Soviet Union.

In the morning, Gorbachev and Prime Minister Toshiki Kaifu discussed the Middle East, Cambodia and other problem areas in the second of three scheduled meetings, officials said.

The third was set for Wednesday evening and officials said a fourth was possible if progress was made on a territorial dispute that has prevented Tokyo from offering the massive infusion of aid and investment the Soviets need.

Both sides agreed not to comment on the progress until later.

During the morning meeting, Gorbachev stressed his close relationship with and admiration for President Bush, a key point in improving Soviet-Japan relations because of Japan's long alliance with the United States.

"It was the first time to my mind that a very high evaluation was given to the role of Bush" by Gorbachev, Vitaly Ignatenko, the Soviet president's press secretary, told reporters.

At a luncheon for 2,500 Japanese business leaders prior to the Diet speech, Gorbachev threw out most of a prepared text and sought to persuade potential investors that he is pursuing serious economic reform.

"We invite you to cooperate," he said, adding that the Soviet Union has much to learn from Japan's experience of converting military industries to commercial use.

Afterward, however, many of the Japanese reacted coolly to investing in the unstable, backward Soviet economy. Some demanded the two countries resolve Japan's claim to islands seized by the Soviet Union during World War II.