The Democratic front-runner in the mayoral race, Fernando Ferrer, raised double the amount of campaign contributions in the past six months compared with his previous fund-raising cycle, a sign that his campaign is gaining momentum.

Mr. Ferrer, the former borough president of the Bronx and the only candidate who beats Mayor Bloomberg in head-to-head polls, will report collecting $1.2 million since mid-July when he files with the Campaign Finance Board on Monday, the next disclosure deadline, officials from his campaign said yesterday. The new contributions bring his campaign war chest is up to $2.5 million.

Another contender, Rep. Anthony Weiner, had an equally successful six months, raising $1 million for his mayoral campaign. Between that and a $225,000 transfer from his federal campaign account, the Brooklyn-Queens congressman’s total will be $1.7 million – more than three times his July tally – when he files with the board, as all candidates participating in the public financing program must do.

Both candidates, however, still trail the speaker of the City Council, Gifford Miller, who collected $1 million in the most recent period and boosted his campaign bank-account balance to $4.3 million. Mr. Miller’s new campaign manager, Brian Hardwick, who worked on Senator Lieberman’s campaign in the Democratic presidential primary last year, said raising money early would allow the Miller camp to focus on “other priorities” later.

“We are obviously encouraged by the early support,” Mr. Hardwick, who has been with the Miller campaign since last Thursday, said. “We feel like this really puts our campaign in a strong position.”

Despite his fund-raising prowess and his prominent position as the council speaker, Mr. Miller seems not yet to be resonating with voters as he’d like to. According to a Marist Institute poll from last month, Mr. Ferrer receives support from 51% of registered voters, compared with 39% for Mr. Bloomberg. In match-ups with the other four Democratic aspirants, the mayor was in dead heats with Mr. Miller and the borough president of Manhattan, C. Virginia Fields, and would only narrowly defeat Mr. Weiner and a council member from Brooklyn, Charles Barron.

Mr. Miller’s aides, who obviously hope to change that, noted that he has several upcoming fund-raising events scheduled, including one next Thursday for which the host is Vice President Gore’s daughter Karenna Gore Schiff.

The campaign manager for Ms. Fields, Joseph Mercurio, said his candidate would report an added $215,000 to the $907,684 she had already raised. He attributed the modest amount to the time Ms. Fields devoted to helping in the presidential campaign.

Plus, he said, most of the Democrats who will face off in the primary will probably meet the $5.7 million spending limit once their contributions are matched.

Mr. Mercurio predicted that Ms. Fields would be in competitive shape for the primary race and dismissed the notion that raising money early was a significant advantage. The proof, he said, was in the last election, when Alan Hevesi, Mark Green, and Mr. Ferrer were up against each other in the primary.

“If you remember, Hevesi announced that he had the most money just like Miller did this past July, the most money the earliest, and he came in last,” Mr. Mercurio said. “Freddy struggled to raise money right up until August, and he ended up maxing out and getting into the runoff.”

Mr. Ferrer ran first in the 2001 primary, but Mr. Green won the runoff before losing to Mr. Bloomberg in November 2001.

Mr. Barron said yesterday he would report raising $35,000, bringing his total to approximately $48,000. He was quick to point out, however, that money was not at heart of his campaign.

“I’m not going to be able to match these people with money,” Mr. Barron said, “but I will be able to match them with message.”

The deadline for accepting contributions for this filing cycle was Tuesday. The CFB is to release the official tallies Monday.