The studies on Melencolia I which have been written up to now, have focused on the iconography of the engraving. Despite the efforts undertaken by several generations of investigators the results remain full of contradictions. The present article tries to search for melancholy content in reading the artistic structure of Dürer's work. The composition of the engraving makes it impossible to build on its basis the coherent iconographical whole. This results from the very nature of melancholy, which is an undecidable state of the human mind. Dürer tried to depict directly melancholic emotion. He also tried to create the allegorical vision of melancholy. However, he failed to relate the two artistic modes of representation because he was unable connect the undecidable aspect of the composition with he allegory, the latter requiring clear and precise rendition.