House Democrats increased pressure on their leaders yesterday to join in opposing the MX missile as debate began on a $188 billion fiscal 1984 military procurement bill.

More than 30 Democrats addressed an emotional party caucus in the morning to express what one freshman called their "frustration and disappointment" that most House Democratic leaders supported the Reagan administration in a crucial MX vote last month. A majority of House Democrats voted against the president.

Several hundred people on the west steps of the Capitol then heard three presidential candidates and assorted other Democratic politicians attack the MX during a noontime rally.

House leaders agreed to postpone until after the July 4 recess a vote on authorizing funds for the first of 100 MX missiles President Reagan wants to build. MX opponents, who have launched advertising and letter-writing campaigns in the districts of several congressmen who supported the nuclear freeze and then voted for the MX, said the delay could give them time to turn the House around.

"I think we've got a shot at it," Rep. Barney Frank (D-Mass.) said after addressing the rally. "I didn't think we did before, but I think the atmosphere now is tightening."

The administration in the meantime was able to defeat three attempts to cut or amend its record weapons procurement request on the House floor in the afternoon. The most serious challenge to the administration's program, an amendment to delete funds for production of chemical weapons, is expected to be considered today.

The House defeated, 243 to 177, an effort to slow development of a satellite-killing weapon, which is scheduled to be tested for the first time this summer. Opponents said once the miniature weapon is tested an arms control agreement to keep weapons out of space will be almost impossible to achieve, but Defense Secretary Caspar W. Weinberger implored the House not to cut funds for the program.

"While we empathize with those persons wishing to see space as a medium free of weapons, the reality of the situation is that we cannot allow ourselves to ignore Soviet space systems which can put our forces at an intolerable disadvantage," Weinberger wrote to Rep. Melvin Price (D-Ill.), chairman of the House Armed Services Committee.

The House also endorsed, 252 to 171, the administration's request to enter into a multi-year contract to buy 100 B1 bombers at more than $200 million each. Supporters said a multi-year contract for the controversial plane would save money, while opponents argued unsuccessfully that it would lock Congress into the full purchase even if budget problems force scaling back of other weapon programs in coming years.

Finally, the House defeated, 283 to 124, an amendment by Rep. Mel Levine (D-Calif.) to reduce purchases of the Bradley armored troop carrier, which critics contend would be vulnerable to antitank missiles on a battlefield.

Ninety-one Democrats, including Majority Leader James C. Wright Jr. (D-Tex.) and Whip Thomas S. Foley (D-Wash.), voted for continued development of the MX missile last month. While conceding doubts about the military value of the $16 billion program, many said support for the president's position would convince Reagan to try harder at arms control talks with the Soviets and would avoid giving the president a potent political weapon to use against Democrats.

"I thought it might have been a mistake if the Democratic leadership had taken a partisan stance and had been seen as obstructing the defense of the country," Wright said after yesterday's caucus. "A given weapon system never to my knowledge has been a matter of party position or partisan contention."

Other Democrats said they believed the votes of the leaders and other Democrats nullified what might have been a valuable political issue, especially as the party's presidential candidates oppose the MX and attack the president's arms control record. Rep. Jim Bates (D-Calif.), one of the freshmen who requested yesterday's caucus, said he wondered why the party did not stick together.

"If we weren't going to take a position on defense as a party, I wanted to know why," Bates said. "As a freshman, I'm not accustomed to questioning the leadership. But in this case we were frustrated and disappointed, and felt we had to question them . . . . It seemed as though they were out of step with the party on this issue."

Rep. Les Aspin (D-Wis.), an MX supporter, said he reminded Bates during the caucus that the MX was "a Democratic weapon" that President Carter supported. He added, however, that he would reevaluate his position "if by the end of the summer" Reagan has not moderated his position further on arms control.

Sens. Alan Cranston (D-Calif.), Gary Hart (D-Colo.) and Ernest F. Hollings (D-S.C.), all candidates for president, joined Sen. Edward M. Kennedy (D-Mass.) and several congressmen in addressing the anti-MX rally.

"The missile makes no sense in terms of arms control or diplomacy," Hart said. "It is not a bargaining chip. And for those Democrats who voted for it as a bargaining chip, shame on them."

Rep. Thomas J. Downey (D-N.Y.), who also spoke, said seven or eight congressmen who voted for the MX in May have decided to vote against authorization of funds for it next month. Opponents would have to switch about 27 votes to kill the missile, he said.