PROBLEM TO BE SOLVED: To provide a technology to prepare highly cytotoxic NK cells of high purity from hematopoietic precursor cells without using animal serum or feeder cells.SOLUTION: The pharmaceutical composition for cell therapy of the invention comprises NK cells obtained by a NK cell-preparing method comprising a step of proliferating hematopoietic precursor cells under a single culture condition containing IL-15, SCF, IL-7 and Flt3L, and a step of inducing differentiation of the cells obtained in the proliferation step into NK cells under a culture condition containing IL-2 for 5, 6, 7, 8 or 9 days. The pharmaceutical composition for cell therapy of the invention may be used for treatment of infectious diseases and/or cancer. The pharmaceutical composition for cell therapy of the invention may further contain TPO.
