An object of the present invention is to provide a method for treating defects of articular cartilage or meniscus of a patient using in vivo chondrogenesis of synovium-derived MSCs. The present invention provides a method for treating a disease associated with defects of cartilage or meniscus. In the present invention, the method for treating a disease associated with defects of cartilage or meniscus comprises the following steps: culturing ex vivo autologous synovium-derived mesenchymal stem cells (MSCs) implanting the MSCs such that said cartilage defect site or meniscal defect site is covered by the MSCs and regenerating cartilage tissue at the cartilage defect site or meniscal defect site in situ by differentiating the MSCs into cartilage cells.
