<p>The present invention pertains to: a novel cyclic peptide derivative that exhibits a CXCR4-antagonizing action; a method for the production thereof; and the use of the derivative in the prevention and/or treatment of autoimmune disorders such as AIDS, leukemia, tumors (proliferation / metastasis) and chronic rheumatoid arthritis, and in a pretreatment for the acquisition of hematopoietic stem cells to be used in stem cell transplantation or the like.</p>
