The present invention provides a monoclonal antibody that recognizes a lipid substance on an iPS cell surface and an ES cell surface as an epitope, and does not recognize EC cells, the antibody having a cytotoxic activity against a target cell, a method of producing a uniform differentiated cell population free of an undifferentiated cell, including contacting a cell population differentiated from an iPS or ES cell with the above antibody, and recovering viable cells, an agent for a cell transplantation therapy, containing a differentiated cell population obtained by the method, and the like.
