The Dimension Data rider, back in the limelight after three below-par Tours, is now four shy of the all-time stage win record of Belgian great Eddy Merckx.
Cavendish, who had not won more than three stages on the Tour since 2011, was just too fast for the rest of the bunch, comfortably beating Norway's Alexander Kristoff (Katusha) in a bunch sprint after 208.5-km of riding from Montelimar.
World champion and green jersey holder Peter Sagan (Tinkoff) finished strongly to take third place while German Kittel finished fifth, protesting as he felt Cavendish had veered towards him during the sprint for the line.
"The difference this year (with 2015) is the track (preparation for the Olympics) but not just that. To be fair I feel exactly the same, it's just that you need to be patient," said Cavendish who followed Kittel's wheel before making his move, powering away to victory.
"I think I'm being more patient than I was last year."
Cavendish insisted his sprint was clean, even if Kittel had a slightly different point of view. The German was gesticulating angrily before he even crossed the line.
"I started my sprint super fast with 220 metres to go, the train worked well. I was in the inside, I was well positioned," he said.
"I saw Cavendish passing me and he swerved to the right and I needed to brake to avoid a collision. It's not up to me to decide if he made a mistake."
Frenchman Jeremy Roy (FDJ), Cesare Benedetti (Bora Argon 18), Swiss Martin Elmiger (IAM) and American Alex Howes (Cannondale-Drapac) broke away early on and built a maximum advantage of 4:45.
Howes was dropped by his breakaway companions with 14km left and Benedetti fell off the pace 9.5km from the line.
Roy and Elmiger were caught with 3.4km left, shaking hands as the peloton reeled them in.
Yellow jersey holder Chris Froome (Team Sky) finished safely to consolidate his advantage after gaining time on his main rivals in Friday's individual time trial.
"I was tired this morning but fortunately this day was a gift for the GC riders, it was a quiet day," he said.
The riders observed a minute's silence at the start with Sagan, Froome and French champion Arthur Vichot in the front of the peloton in memory of the 84 victims of the Nice attack just eight months after gunmen killed 130 people in Paris.
Sunday's 15th stage is a gruelling 160-km trek in the Alps between Bourg-en-Bresse and Culoz.
"It's a key stage," Froome warned.
