Fernando Belaunde Terry, the 67-year-old architect who was Peru's last democratically elected president, appears to have won yesterday's general election here and will reoccupy the presidential office from which he was ousted 12 years ago by a leftist military coup.

Belaunde's supporters and independent political observers attributed Belaunde's strong showing to a rejection by Peru's 17 million citizens of more than a decade of military rule.

"He is perceived as a bullfighter, strong and honest," Enrique Zileri, editor of Lima's Caretas magazine, said today. "Belaunde took votes from the left, the right and the center in . . . a vote against the arbitrariness and lack of freedom under military governments."

Although the official vote count will not be available until sometime next month, unofficial returns compiled by computers of the three major television stations here indicated that Belaunde received between 42 and 44 percent of the 4 million valid votes cast. The general election was Peru's first since 1963, when Belaunde was elected to the presidential term he did not complete.

Balaunde's percentage could decrease after the official count is completed but all observers here agree it cannot go below the 36 percent figure that would throw the election into the Congress, which also was elected yesterday.

The biggest losers in the election were the populist American Popular Revolutionary Alliance, Peru's oldest and best organized political party, whose candidate, Armando Villaneuva, recieved only about 26 percent of the vote, and the country's five major leftist parties, which together received only about 17 percent of the vote.

Belaunde also took votes from the right. Luis Bedoya Reyes, a popular former mayor of Lima favored by much of the business and upper classes here, received only 11 percent of the vote, 3 to 4 percent less than he had hoped for.

Belaunde said, "The Peruvian people have . . . voted for the constructive development of the country. this is the secret of Accion Popular," the centrist political party Belaunde founded more than 25 years ago.

Belaunde said today that his first priorities on assuming office on July 28 will be to provide 1 million jobs for the unemployed, to increase food production, return the country's newspapers, confiscated by the military after the 1968 coup, to their owners and to create programs to develop Peru's economy.

Peru is plagued by unemployment of at least 20 percent, and inflation is running close to 70 percent.

Manuel Ulloa, who will probably serve as finance minister in the new government, said Peru would need loans as well as other economic and technical assistance from abroad, particularly the United States. The Carter administration has strongly backed Peru's return to elected government, but its ability to come to the new government's assistance with major aid is doubted.

The U.S. aid program has been significant reduced in real terms in recent years and Congress is now threatening to cut $100 million from the promised U.S. contribution to the Inter-American Development Bank, an important source of development loans for noncommunist Latin countries.

Nonetheless, of the 15 presidential candidates in yesterday's election, Belaunde should receive the most sympathetic ear in Washington. He is decidely pro-American, having lived and been educated in the United States. After being exiled in 1968, he spent seven years working as a professor at such U.S. universities as Harvard, Columbia, Johns Hopkins and George Washington before being allowed to return home.