SANTA BARBARA, Calif. (AP) _ About 30 demonstrators disrupted a news briefing by White House spokesman Larry Speakes on Thursday, breaking a window and yelling protests about the House approval of aid to the Nicaraguan rebels.

Some of the demonstrators attempted to push their way into the briefing room that the White House press corps uses when President Reagan is at his Santa Barbara County ranch. The protesters broke a window in the process.

They carried placards reading ''Stop the war in Nicaragua'' and yelling ''Reagan is a fascist.'' They were prevented from entering the room at the Santa Barbara Sheraton Hotel by White House aides and several members of the press corps.

The group, identified by one of the participants as ''The Emergency Response Network for Central America,'' dispersed after several Santa Barbara police officers arrived.

One protester, Frances Dwight, said the group was ''upset about the aid - we wanted to get President Reagan's attention.''

The House on Wednesday night gave Reagan a hard-fought victory on his request for $100 million in mostly military aid to Nicaragua's anti-government rebels. The legislation passed by the House still must be reconciled with a Senate version before the president signs it into law.

Speakes, who had just begun the day's news briefing when the protest broke out, started the session after a 30-minute delay.

The White House had hired a private security guard to help protect the press area, following a similar protest during Reagan's last visit to Santa Barbara over the Easter holiday.

During that demonstration, protestors entered the briefing room and spilled fake blood on themselves before dispersing peacefully.

White House press aide Mark Weinberg said he was unaware of any arrests following the demonstration.

Speakes holds periodic briefings for the White House press corps and local reporters in the hotel while Reagan vacations at his mountain-top ranch about 26 miles outside Santa Barbara.

The spokesman said Reagan, who is on a five-day respite at his ''Rancho del Cielo,'' dealt with routine paperwork Thursday morning and planned to go horseback riding and either chop wood or clear brush during the day.

Speakes said the president and his wife Nancy had breakfast together and that the couple was enjoying sunny and warm weather at the ranch.

They are scheduled to return to Washington on Monday.