The present invention provides a particulate composition containing: block copolymer units being arranged radially with hydrophobic polymer-chain segments radially inside and hydrophilic polymer-chain segments radially outside; and a charged lipid which carries a charge opposite to the charge of a drug to be encapsulated, the charged lipid being attracted to the hydrophobic polymer-chain segment. In this particulate composition, the drug is retained within the particle via electrostatic binding with the charged lipid, whereby the outer surface of the particle is prevented from being charged to attract a substance which has a charge opposite to that of the charged lipid.