Bomb disposal experts summoned to the scene destroyed the object, which appeared to have been made to look like a fake bomb, a Stockholm police spokeswoman told DPA.
The Kungstradgarden Station is the end station on one of the capital's underground train lines.
No threats have been reported in connection with the incident. Stockholm police were treating it as a deliberate hoax and a case of "gross nuisance alarm".
Security in the Swedish capital has been elevated since a suicide attack Dec 11, when a 28-year-old man was killed in a blast. The dead man, who sent a threatening email just minutes before the attack, was the only fatality. Two bystanders were wounded.
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