The research deals with transformation of the subject matter of Husserl's phenomenology in Martin Heidegger's philosophy. The research explores why even with remarkably similar philosophic opinions shared by Husserl and Heidegger the latter had to give up his position of a teacher and to express differently the subject matter of the phenomenology. While answering this question, two approaches are undertaken. The first one deals with the phenomenology as transcendent philosophy: the research underlines that transcendental ego is a complicated matter, which eventually revealed itself as ultimate. The second approach calls for an entire change of the phenomenology. This approach embodies the fact that a taking-out-of-the-context method cannot be applicable for all areas of reality. Thus, the dimensions of reality that practical aspects deal with, including taking out of the context, are basically inaccessible for being taken out of the context. This is why the demand for Being comes to be essential. As a result of this demand, Husserl's phenomenology loses its position for, from now on, first, Being itself takes the place of transcendental I; second, intentionality appears to be an existential attitude; third, phenomenology as well as the truth gets a new meaning; forth, a concept of transcendental philosophy modifies substantially. Thus, the research explains the point that in passing over the basic settings of Husserl's philosophy it was crucial that Heidegger realized a priority role Being itself plays as regards to any means of Being, including pure consciousness.