It was the seventh stage won on the Tour by the Briton, who is now one victory short of the British record held by Barry Hoban since 1975.
Perfectly led by Columbia team-mate Mark Renshaw in the final stretch, Cavendish was too strong for green jersey holder Thor Hushovd of Norway, who came home second on the 10th stage in front of American Tyler Farrar.
“I was afraid I may have attacked from too far, but Renshaw helped me out. He was great today,” Cavendish said.
Ireland’s Nicolas Roche finished 10th in yesterday’s Bastille Day stage.
The AG24-La Mondiale rider now lies 50th in the general classification, 16 minutes 45 seconds behind the yellow jersey.
The peloton, who rode at a relatively slow average speed of 40.7 kph, caught a four-man breakaway in the last two kilometres.
Italy’s Rinaldo Nocentini retained the overall leader’s yellow jersey.
After several meetings on the rest day in Limoges, teams had reluctantly accepted to start the stage without earpieces or equipment allowing riders to communicate with their team cars.
“We’re very, very disappointed. But it’s not over,” said Astana team chief Johan Bruyneel, who had led a petition of 14 teams against the ban.
Seven-times Tour de France champion Lance Armstrong also said he thought it “better to have them (earpieces)” but had decided against a strike.
“I’m against a strike. Teams don’t like it, sponsors don’t like it,” the American said.
Armstrong predicted that the 13th stage to Colmar, also scheduled to take place without any communication device, would see the UCI back down on their position: “My prediction is we’ll have earpieces on Friday,” he said.
However, International Cycling Union (UCI) head commissioner Martin Bruin said there was no plan to overturn the decision: “The stage will be held without radio as planned,” he told French television.
Four riders took advantage of the leisurely pace to break away on Bastille Day. Frenchmen Samuel Dumoulin, Benoit Vaugrenard and Thierry Hupond went almost on the gun along with Russia’s Mihail Ignatiev, who was parting company with the peloton for the third time on this Tour.
Perhaps because of the radio-ban, the main pack always refused to let them take too much time and their lead topped at 3:50 before settling at around 1:30 for most of the second half of the race.
They were finally caught with two kilometres to go, leaving centre stage to the sprinters.
Cavendish held off Hushovd in the sprint. The green jersey never seemed capable of coming off the wheel of the British sprinter, who now has a total of seven Tour de France stage victories.
“I braked a little bit too much and I lost four or five metres on Cavendish and I had to spend too much energy to close the gap,” said Hushovd.
Cavendish will be the favourite again in today’s 192-kms 11th stage from Vatan to St Fargeau. “I will try. There are only three days left for sprinters, the two stages ahead, then the Champs-Elysees,” he said.