The paper considers a question, which concerns such values that the historians of philosophy elaborate when doing their work. It is a commonplace situation when the representatives of professional circles turn to history of philosophy to find the material for self-reflection; they conceive history of thought to be a tool to find or establish distinctness in their own philosophizing. We think that the variety of values could be principally reduced to the discussion and founding the status of philosophy as such. Correspondingly, we will point at three leading axiological principles (which are: didactical, legitimizing, communicative) in the historical-philosophical studies. Finally, we add and consider the fourth principle, namely existential-practical, to the mentioned three, which reckons the ancient maxim of self-knowledge.