The drone is of a similar type to the three found in southeastern Finland at the end of March, according to a statement.
The area, a forested area in Itis, has been cordoned off, and the military will defuse the warhead.
It is unclear where the drone comes from, but at least two of the previous drones have been confirmed to be Ukrainian.
Ukraine has apologized, saying the drones that were heading toward targets in Russia were probably electronically disrupted by Russia.
In recent weeks, Kyiv has attacked Russian energy facilities at ports on the Gulf of Finland, near Russia's border with Finland.
