We report our intensive in vitro experiments in which we have implemented and executed several finite-state automata in test tube. First, we employ the length-encoding technique proposed and presented in [4, 3] to implement finite automata in test tube. In the length-encoding method, the states and state transition functions of a target finite automaton are effectively encoded into DNA sequences, a computation (accepting) process of finite automata is accomplished by self-assembly of encoded complementary DNA strands, and the acceptance of an input string is determined by the detection of a completely hybridized double-strand DNA. Second, we design and develop practical laboratory protocols which combine several in vitro operations such as annealing, ligation, PCR, and streptavidin-biotin bonding to execute in vitro finite automata based on the length-encoding technique. We have carried laboratory experiments on various finite automata of from 2 states to 6 states for several input strings. To our knowledge, this is the first in vitro experiments that have succeeded to execute 6-states automaton in test tube.