無期待可能性是指，處境特別艱難的行為人，社會難以期待這個人能夠有合于規範的行為，儘管不能找出明文規定的排除罪責的事由，但也可以依照欠缺「他行為可能性」的法理，承認「無期待可能性」屬於一種超法律的阻卻罪責事由。德國學界長久以來的爭執，也就是「無期待可能性」能否當作超法規的阻卻罪責事由。我國實務對於無期待可能性所採的態度幾乎與德國實務相同，雖然不是完全的拒絕，但在判決裏看不到明確的承認。無期待可能性的概念在創用當時，是運用在過失犯罪的領域，以之限縮注意義務的範圍。後來某些德國刑法學者試圖擴大適用範圍，但並沒有被廣泛的接受，德國實務的態度更是謹慎與保守。本文所舉的原住民的例子，雖是故意的作為犯。但是如果處境真的是非常艱難，應該可以例外的依照無期待可能性的概念排除或減輕罪責。因此，我國實務還可以再更大膽的採用無期待可能性的觀念，作為判斷行為人是否負責的根據。

Impossible expectation means to provide ground as an affirmative defense for a person who is in difficulty. Because we cannot expect the actor behaved reasonable behaviors fitting norms. Even though, it could not be specified statutory affirmative defenses that it still can be made with the theory of possible expectation of behavior specified as de jure decriminalization. As to its appropriateness and applicability, after years, the arguments among German-based criminal law scholars on what if impossible expectation could be viewed as de jure decriminalization never ever being stopped. On the same issue, judicial practice in Taiwan almost open the same opinions with German that courts may not totally reject the concept of Impossible expectation, but made obscure judgments on cases.At early stage, the concept of impossible expectation is applied to negligence which could narrow down the scope of attention duty. Some criminal law scholars attempted to expand the extent and application of impossible expectation but that was not accepted as widespread belief. In German, courts even much conservative and hesitated.The article takes the case of indigenous people commits the acts intentionally as an example. If the situation is difficult to the actor, I suggested the concept of impossible expectation could be applied to eliminate or reduce the criminal responsibility for the actor exceptionally. Therefore, courts may adopt impossible expectation in fulll-scale scope boldly, because that is the ground of judging a person to take criminal responsibility.