The underground station wasn completely shut during the incident, which began at around 11.45 and ended an hour later.
Several fire engine units attended the scene and fire fighters were seen entering the station with hoses.
Shocked commuters on social media claimed the fire either began at a platform or on one of the escalators.
One video taken by a commuter showed smoke rising from an escalator in the station.
TWITTER / DANNYRAMPLING
London Bridge station has been evacuated due to a fire
London bridge evacuated, apparently fire on the escalator
One said on social media: "Just been evacuated from London Bridge tube. Staff saying 'fire on platform'. Eek.
Another said: "#Londonbridge evacuated apparently fire on an escalator #tube"
One commuter advised others to "avoid" the "madness".
A Transport for London spokesman said there is "no indication of when London Bridge" will open.
TWITTER / CHRISSCHOFIELD1
Fire fighters at the scene in London Bridge this lunchtime
He said: "The fire is ongoing but it does not look like it is that concerning.
"Fire fighters are on their way."
TWITTER / RACHEL CARY
A station staff member assisting commuters during the evacuation
Northern Line and the Jubilee Line underground trains did not stop at the station during the incident.
Twitter accounts for both lines Tweeted: "London Bridge – station closed. Fire alert. Trains not stopping."
Normal service has now resumed.
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