The study aims to shed light onto the circumstances which prompted M. Heidegger to change direction of his philosophical enquiry in the early 30s of the XX century. The authors determine the need for transition from dividing M. Heidegger’s creative work into the early and the late periods to considering periodisation of M. Heidegger’s creative work according to themes of his writings. Heidegger I works out a project dedicated to preserving and transforming the German spirit, while Heidegger II focuses on ultimate ontological issues. Scientific novelty of the research lies in the fact that the above-mentioned turning point in M. Heidegger’s philosophy is considered with regard to the worldview of the thinker himself, on the basis of the tasks he set himself. As a result, certainty is achieved regarding understanding of the philosopher’s reasons for changing direction of his philosophical enquiry, in particular, impossibility of implementing a university reform in political climate of Germany in the early 1930s.