The invention relates to a direct-plug switch balance lock, which comprises: lock element, lock muffle, movable bolt, and bolt recover spring, wherein it is characterized in that: the inner side of keyhole has key channel, balance lever, first locking plate, and locking lever; when the key is not inserted, the balance lever, via the recover spring, uses its hoop to buckle the edge of first locking plate to avoid moving it; the locking lever, via the recover spring, inserts its upper hoop into the positioning hole of first locking plate and uses the lower hoop to buckle the positioning hole ofsecond locking plate to avoid moving it; the bolt connected to the second locking plate clamps the groove at the free end of lock muffle to avoid moving lock muffle; when the key is inserted, it can lift up the balance levers to the balance position, to release the first locking plate to unlock. With said invention, the lock can be unlocked by using matched key.