Objects of the present invention are to provide a compound which is useful as a surface modifier for producing a drug carrier or the like, or a salt thereof; a fine particle comprising the same; and the like. The present invention provides a compound in which a substance to be modified, which is selected from the group consisting of an amphiphilic substance and a hydrophobic substance, is modified with a glycerol derivative represented by the following formula (1): wherein R represents a residue comprising a reactive group for the substance to be modified, which is selected from the group consisting of an amphiphilic substance and a hydrophobic substance or for a spacer capable of binding the substance to be modified, which is selected from the group consisting of an amphiphilic substance and a hydrophobic substance, to R-X, or a group capable of being transformed into the reactive group; n represents an integer of 3 or more; and X represents a residue capable of having the following structure by n in number: directly or via the spacer, or a salt thereof; a fine particle comprising the same; and the like.