Secretary of State Cyrus Vance and Rosalynn Carter met today with members of Nicaragua's revolutionary government, and both sides said they had decided to forget the past and make a new beginning in U.S.-Nicaraguan relations.

The United States held out the possibility of military as well as humanitarian aid, and the Nicaraguans reaffirmed their pledge to respect human rights.

"Whatever happened in the past, it is time for a new beginning," said the Rev. Miguel d'Escoto, a Maryknoll priest who is Nicaragua's foreign minister."It is time for forging a new relationship."

Also at the meeting were Eden Pastora, the Sandinista guerrilla leader known as "Commander Zero," and Violeta Chamorro, a member of the governing junta.

State Department spokesman Tom Reston said both sides "emphasized that they wanted to put the past in the past." He said Vance told the Nicaraguans the United States wanted friendly relations with the revolutionary government.

Vance and the Nicaraguans are among a large number of high-level officials in Quito for the inauguration today of Jaime Roldos as the first popularly elected president to succeed a military government in South America in six years.

Reston said the Nicaraguans declared they would invite the Inter-American Commission on Human Rights to Nicaragua - as they had promised earlier - and "indicated that their promises to the Organization of American States still stood firm."

He was referring to a letter to the OAS in which the five-member Nicaraguan junta, then in exile, guaranteed the rights of supporters of president Anastasio Somozo when the junta came to power. The letter is believed to have been part of a deal worked out with the United States that resulted in Somoza's resignation.

The U.S. insistence on guarantees human rights is intended to reassure both conservatives in Washington who fear Nicaragua will become another Cuba and the right-wing military governments in Central America that fear a fate similar to Somoza's.

The talks with the Nicaraguans were part of a series Vance scheduled with officials of both the Central American governments and democratic Latin American governments that supported the successful Sandinista rebellion.

The situation in Current America was expected to be a major topic in all Vance's meetings.

The U.S. government has been debating whether to resume military aid to El Salvador and Guatemala, which have been criticized for widespread violations of human rights.

Vance and Mrs. Carter lunched with Colombian President Julio Cesar Turbay and Vance met with the foreign ministers of Ecuador and Colombia.

Nicaragua's new government has also requested military aid, and Reston said the requires "will be explored in the future."

The presence of so many high officials at Roldos' inauguration demonstrated the importance attached by hemispheric nations to the decision by the military junta that took power here in 1972 to bow out.

But the Nicaraguans were clearly the stars of the event for the Ecuadorans who gathered in the crisp, sunny weather to watch dignitaries arrive at Quinto's Legislative Palace.

Commander Zero, wearing fatigues and a beret, was mobbed by young people chanting "Viva Nicaragua."

The ceremony in which Ecuador's three-man junta formally turned over power to Roldos was accompanied by pageantry that recalled caricatures of Latin American dictatorships.

The honor guard lined up along a red carpet at the palace wore white-and-blue 18th century uniforms with blue kepis covered with gold braid, black riding boots and silver spurs. They presented arms with fixed bayonets.

In contrast, stationed alongside the honor guard were members of Ecuador's special forces wearing camouflage fatigues and red berets. Even the brass band that played the national anthem was made up of special forces.

In the modern ampitheater where the newly elected 69-member Congress will meet, Roldos, 38, and Vice President Oswaldo Hurtado, 39, sat on the dais surrounded by generals and admirals festooned with battle ribbons and gold braid.

Roldos, in his speech, made clear that he intends to steer a new course. He reminded his listeners that he won more than two-thirds of the vote in a presidential runoff election April 29 and vowed to direct his efforts toward improving the lives of the poor - who make up a large majority of the 7.6 million population.

It has been estimated that only about 2.5 million people participate in the money economy, while the rest - most of them Indians - barely subsist in the underdeveloped rural area or urban slums.

Roldos plecged to fight corruption, discipline crooked judges, improve health care and education, redistribute rural land holdings and expand exploration for oil.

Ecuador's jungle oil fields produce about 200,000 barrels a day, of which about 115,000 are exported. Some experts predict, however, that if domestic consumption continues at the present rate, the country will have to import oil by 1985, the year Roldos' term expires.

Addressing the high-level foreign visitors, Roldos said, "The latin Maerican political map shows two antagonistic areas" - democracies and dictatorships.

"History shows that regimes of force make it impossible to have economic development, political democracy and social justice," he said. Then, in an apparent criticism of leftist radicals, he added. "My government will demonstrate that economic development and social justice are fruits of the orchard of democracy and not of terror."

He added a special greeting for each head of government and Mrs. Carter, praising her husband as a defender of human rights.

The last time a South American military government handed over power to a freely elected leader was in 1973, when Hector Campora became president of Argentina. Now Argentina and most South American countries are under military rule.

Bolivia also held an election recently but a dispute after the vote resulted in a compromise choice for president with a new election set for next year. Neighboring Peru also plans an election next year.