The purpose of the present invention is to provide a disaccharide compound which can be optimally used to obtain a modified organopolysiloxane compound having excellent surface-active action. A further purpose is to provide a modified organopolysiloxane compound obtained using said disaccharide compound, a surfactant containing said modified organopolysiloxane compound, a cosmetic containing said surfactant, a foam material and a coating material. This disaccharide is characterized by being obtained by reacting disaccharide with a compound having an allyl group and an epoxy group.
