A drawstring lock includes a housing that allows the two ends of a drawstring to pass through, a stop mechanism disposed on the housing, and a lock mechanism connected to the stop mechanism. The housing is able to shift freely along the drawstring and once reaching its desired position, it is able to operate the stop mechanism so that the housing is stopped and cannot be shifted. Subsequently, the lock mechanism is used to lock the stop mechanism, keeping it secured until the lock mechanism is unlocked.