Pentti Savola, 58, was among a group of early morning commuters waiting to get a bus to work when the animal came up to him and bit his leg last week.
"It was lightning fast. I never thought that an animal that looks so clumsy could be so crafty," he told Swedish news site mitti.se.
He said that he may have stressed the animal out when he tried to take a photo of it with his mobile.
But after his own stressful experience, he said he wanted to tell his story to warn children that they should not pet beavers without knowing more about the animals.
Savola was not hurt in the attack.
The beaver was hunted to extinction in Sweden by the end of the nineteenth century but was reintroduced during the 1920s and 1930s after eighty of the furry animals were imported from Norway, in what is often cited as one of the most successful animal conservation efforts in history.
The wood-loving, sharp-toothed, primarily nocturnal, semi-aquatic animals are the second largest rodents on the planet (after the capybara) and are most prevalent in North America.
Savola's experience in Tyresö is not the first time the sharp-toothed beasts have caused chaos for commuters in Scandinavia.
In November 2013 drivers in central Sweden were left in a jam near Borensberg in Östergötland, after police blamed a beaver for felling a tree, which resulted in a blocked road and long queues of motorists.
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Police were also called to help a homeowner deal with a wayward Swedish beaver that had found its way into a resident's garage in Nässjö in central Sweden in 2011.
And a decade ago one of the creatures made global headlines after it caused a blackout by munching through cables owned by Swedish energy giant Vattenfall.