The purpose of this article is to lay out an attempt to analyze the concept of immanence in the famous work of Martin Heidegger «Being and time». Undoubtedly, as we will remind throughout the entire work, the very concept of immanence, taken in the strictest sense of the word, cannot be applied to the philosophical calculations of Heideggerian philosophy without, in one way or another, changing the very essential foundations of his philosophy. However, our analysis is aimed, without touching on these grounds, to trace a possible way to clarify those conceptual premises that could reveal, albeit not in an explicit form, the inner structure of Heidegger's philosophical project, or, to be more precise, the way by which within the textual structure itself (and, accordingly, the conceptual and terminological structure), the process of the internal genesis of the immanent space takes place, expressed in the correlative organization of essential constituents, which have the decisive importance both for Heidegger and for our project — being and entity.