Prime Minister Menachem Begin, who since his election in 1977 has survived corruption scandals, two dozen no-confidence motions and resignations by six ministers, decided today to seek new elections July 7, four months before his four-year term expires.

The prime minister indicated that he will stand for reelection. but he is sure to face tough going when the campaign gets under way next spring. Public opinion polls show the opposition Labor Party, headed by Shimon Peres, far out in front of Begin's Likud block.

Most political analysts have forecast a large margin of victory for the Labor Party, although probably not enough to form a government without coalition partners from other parties. Whatever the outcome, the upcoming political campaign, holding out the possibility of realignment in the Israeli leadership, appeared to spell certain delay for any major initiatives in the Camp David talks on Palestinian autonomy.

Begin won Cabinet approval of a bill to dissolve Israel's parliament and schedule the national elections at a date that will keep him in office four consecutive years, more than any other government in Israel's history.

According to the Cabinet decision, Begin's government on Monday will introduce a bill in the parliament setting the vote for July 7. after a debate, the parliament is expected to pass the measure, probably later in the week.

But the election date will be a matter of contention with the Labor Party.

Chaim Bar-Lev, the party secretary, said tonight that the Begin government is "at the end of its rope."

"this is a clear sign the government is not capable of continuing to the end of its term," he added. "But it wants to drag on as long as possible. We are against it. the elections should be held as soon as possible."

Labor sources said a compromise date, possibly mid-june, is likely.

Today's decision followed a week of intensive consultation among the prime minister and representatives of the various factions of this likud coalition, which started to unravel last Sunday after Finance Minister Yigael Hurvitz resigned following a disagreement with Education Minister Zevulun Hammer about a pay increase for Israeli teachers.

Begin was said to have considered appeals by some likud hard-liners to try to patch together a slim majority by recruiting into the coalition some of the parliament's many one-member factons in exchange for political promises. But coalition sources said the prime minister decided to initiate an "honorable" end to his government and take his chances on reelection.

Asked today whether he thinks he can be reelected, Begin replied, "I'm confident, and therefore we're going to the elections at the proper time."

In a meeting with members of the Likud Knesset faction, Begin said, "We will come to the voters with a long list of achievements, the first of which is that after 30 years of war and bloodshed, we were the first administration to have successfully concluded a peace agreement with a neighboring country. this is no trivial thing."

By initiating elections, Begin has the tacit agreement of the Labor Party not to harass the government with no-confidence motions that could force the prime minister to resign.

The Cabinet today took no action in naming a successor to Hurvitz in the Finance Ministry post, which Begin has taken himself on an acting basis. Begin indicated that the next finance minister would come from the liberal faction of the Likud and that the post may be filled this week.