http://nato.gov.si/eng/topic/national-security/neutral-status/neutral-countries/
"Neutral European countries: Austria, Switzerland, Sweden, Finland, Ireland"
Finland derives its policy of neutrality from the period directly following the Second World War. Its interest in remaining neutral in conflicts between great powers was first recognised in a treaty between Finland and the USSR in 1948 (the Treaty of Friendship, Cooperation and Mutual Assistance). The treaty forbids the signatories to join a military alliance against the other, and Finland could not allow its territory to be used for an attack on the USSR. Finland was also bound to preserve its neutrality through adequate armed forces. Finland's neutrality does not have roots in international law, and there are no international pledges for its neutrality. Thus Finland, like Austria, is a case of enforced neutrality, again by the USSR.