The dichotomous division of state security into internal and external aspects is one of the basic classifications of security occurring in the discipline of security studies. In addition, the above- -mentioned issue is also very important from the perspective of Polish legislation, in which there is both the concept of internal security and the concept of external security that constantly accompanies it. Taking into account two factors, firstly, the lack of a legal definition of both of the above-mentioned concepts, and secondly, the inaccuracies noted by the author of this work in the discipline of security science regarding the above-mentioned comprehensions, the purpose of this article is to present the basic difficulties related to defining the first of them, ie the internal security of the state in Poland. This choice is not accidental, because when analyzing the issues of internal and external security, one can see the significant primacy of the first word over the second. The implementation of the purpose of this article was made in a three-stage process. In the first part of the article, an attempt was made to answer the question concerning the genesis of the above-mentioned dichotomy of state security. In the second part, attention was paid to the correctness of the created dichotomy, as well as the presentation of the author’s concept of perceiving both concepts created on the basis of the definition of the terms: security and the state. The third last part was devoted to the analysis of the ways of defining internal and external security in the discipline of security studiesin terms of their correctness. The results of the study showed two basic conclusions. First of all, despite the lack of correctness of the analogy between the dichotomy of threats and security policy on the possibility of dichotomous division of the concept of security in the literature on the subject, it is possible to create this type of dichotomy. Secondly, the main difficulty in defining the internal security of the state in Poland is the lack of functioning in the literature of the subject of the accepted definition of external security, which, by its nature of dichotomy, excludes the possibility of accepting also the definition of internal security.