Vice President Bush, criticized by other Republican presidential candidates for refusing to join them in a debate planned for Oct. 28 and sponsored by public television's "Firing Line," said yesterday that he will take part in the debate.

Bush announced his change of heart in San Antonio after discussing it with aides on the way to a speaking engagement there, the aides said. Negotiators for the vice president, including former New Jersey Republican senator Nicholas Brady, had said last week that Bush was holding out for a debate later in November.

"I know there has been considerable discussion about the 'Firing Line' debate," Bush said in a statement. "I have been invited to participate in the debate by the sponsors who want to hold it in Houston and, while I have already accepted five debates, I am ready to accept a sixth."

Bush said his acceptance is conditioned on the "Firing Line" debate being "first" and being held in Texas. The debate would be the first in which Bush participates, but others have been held without him and more are scheduled before Oct. 28.

The "Firing Line" debate is hosted by conservative William F. Buckley, and the Republican debate has been postponed twice.

Earlier, Bush aides said they did not want to participate Oct. 28 because it was too early and conflicted with their plan to use the several weeks after Bush's formal announcement to hold campaign events. Bush is expected to enter the race in mid-October, but a date has not been announced.

"The vice president has let it be known to me and other members of this campaign all along that he was very interested in doing the debate," campaign manager Lee Atwater said yesterday.

"He allowed us to try to negotiate and get dates that suited the campaign better, but it was his sense that the negotiations were stalled and he wanted to go ahead and let it be known he would debate regardless of the date, and he looks forward to it," Atwater said.

All of the other GOP presidential hopefuls have agreed to participate Oct. 28, and several issued statements highly critical of Bush when he initially refused to attend.

A spokesman for former Delaware governor Pierre S. (Pete) du Pont IV yesterday called Bush's statement a "cautious but welcome first step . . . . We look forward to hearing about Bush's vision for the future.

"It's unfortunate, however, that he had to be cajoled into doing this. Our campaign hopes that he will start talking more about his ideas for the future."