Disclosed is a substance which is not accumulated stably in cells, does not cause the dysfunction of normal cells, and so on, and therefore can be used as an anti-cancer agent or in a DDS without having any adverse side effects. It is found that Hsp90 alone cannot exhibit its function as a chaperone in assisting the refolding of a protein such as survivin, but can exhibit this function when Hop (which is one of the partner proteins of Hsp90) binds to Hsp90. Thus, specifically disclosed herein is a chimeric peptide comprising of an Hsp90 TPR domain binding peptide and a cell-penetrating peptide.
