A co-modified organopolysiloxane having a group having a siloxane dendron structure and a group containing a saccharide component (e.g. a sugar lactone amide alkyl group) is disclosed. The present invention also provides a method for producing the co-modified organopolysiloxane, as well as a surface treatment agent, a powder treatment agent, a powder composition, a powder-in-oil dispersion, a preparation for external use, and the like containing the co-modified organopolysiloxane.
