Studies of causal conditional inference showed that acceptance of the inference decreased when reasoner found the counterexample of the inference. This study investigated how availability of counterexample affected causal conditional inference. In experiments, participants read the stories contained conditional inference statement and judged validity of the inference. Half of the experimental stories explicitly mentioned counterexample of the conditional inference in order to manipulate availability of the counterexample. Results indicated that acceptance of inference was decreased and reaction time of judgment was accelerated when story explicitly mentioned counter example of the inference. Therefore, available information of counterexample affected causal conditional inference by facilitated and shortening the counterexample search.