消滅時效中有關時效不完成制度，在公法領域尚未有統一的明文規定，司法實務及學說上通說認為宜類推適用民法相關規定。不過，在解釋上並非民法所有時效不完成事由皆能為公法領域之情形所適用，而且從法治國家強調依法行政原則、民主原則、法安定性原則、信賴保護原則及平等原則的角度來看，消滅時效不完成宜有法律明文規定才是。本文以德國聯邦行政程序法第53條之更迭及德國租稅通則第171條、第230條規定為例，說明除類推適用民法相關規定外，認為將作成課稅處分前之行政調查期間，及作成行課稅處分後直至該處分不得被撤銷為止的行政救濟期間二者，當作是時效不完成之事由，並說明其理由。同時，針對行政法院判決的見解加以批判，認為有必要將現行時效中斷事由修改為時效不完成事由，將來可避免行政機關的濫用公權力。

The system of unexpired statute of limitations has not been unificated in the area of pubic law, the logically coherent arguments at judicial practice and theory believe that, it is suitable to analogy related stipulation in civil law. Although, in the matter of interpretation not all matters of unexpired statute of limitations in civil law could be adopted in the situation of pubic law. And from the point of view below the rule of law, principles of administration according to law, democracy, stability of law, protection of reliance and equality, the unexpired statute of limitations should be legally defined. The Research about examples of § 53 Federal Administrative Procedure Law and §§ 171; 230 General Tax Law in Germany, beside the analoging to suitable related stipulation in civil law, we need to consider both the period of Administrative investigation before leving tax and the period of Administrative relief after leving tax to canceling the leving, as the matter of unexpired statute of limitations, and to explain the reason. It also criticizes the opinion of administrative court judgment, and it is necessary to change matters of suspended statute of limitations to matters of unexpired statute of limitations, so that in the future we can avoid abusing authority of the administrative organizations.