The present invention relates to a hybridoma cell line producing a PPAR gamma-specific monoclonal antibody, and a method for detecting a PPAR gamma ligand related to the progression of difficult diseases, such as cancer, inflammation and metabolic diseases obesity and diabetes), using the PPAR gamma-specific monoclonal antibody. This PPAR gamma-specific monoclonal antibody and the method for screening a PPAR gamma ligand using the monoclonal antibody will be commercially used for screening a PPAR gamma regulator related to diseases such as inflammatory, cancer and metabolic diseases, and also will serve as an useful tool for analyzing the function of such a ligand.