This article aims to show that formulated by Immanuel Kant distinction between spontaneity and receptivity of perception as two inseparable aspects of it is one of the most important themes in the Heidegger’s reception of Kantian philosophy, since it allows Heidegger to express the principle of circularity of understanding. Martin Heidegger, referring to Kant’s concept of perception, explains that man as there-being (Dasein) is able to see being (Sein) in beings (Seiende) only if one regards them as being (seiende), what one does according to his own being. The analysis of Kant and the Problem of Metaphysics (1929) and the What is a Thing (1935) presented in the article investigates this particular topic.