Traffic was interrupted between 1 and 3pm, Eurotunnel's director for operational communications Yves Szrama told AFP.
The fire was detected around 1300 GMT after it broke out on a cargo shuttle carrying 29 trucks as it travelled towards France and was about seven kilometres (four miles) from the tunnel's exit.
"The convoy was led out of the tunnel on an emergency lane, where it was met by firefighters," Szrama said.
"Only one truck and its cargo was destroyed."
He said none of the 36 people aboard the shuttle, including truck drivers and Eurotunnel staff, were injured.
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Four trains on the Eurostar passenger link, carrying about 2,000 passengers in total, were blocked as a result of the fire, two outside the tunnel in Britain and two outside the tunnel in France.