To control the differentiation of mesenchymal stem cells into steroid hormone producing cells. Mesenchymal stem cells can be differentiated into steroid hormone-producing cells by being stimulated by a transcriptional factor (SF-1), preferably by the transcriptional factor (SF-1) and cAMP. The present invention is a method for differentiating mesenchymal stem cells into steroid hormone producing cells, comprising stimulating the mesenchymal stem cells by the transcriptional factor (SF-1). The mesenchymal stem cells may be further stimulated by cAMP.