The present invention provides a nucleic acid complex with low toxicity and high safety that can persistently maintain a nucleic acid, such as siRNA or the like, in a cell； and a nucleic acid delivery composition that can efficiently deliver the nucleic acid complex into a cell. A nucleic acid complex with low toxicity and high safety that can persistently maintain a nucleic acid in a cell can be obtained by forming a complex using a nucleic acid to be introduced into a cell, and a highly branched cyclic dextrin. Moreover, when a carrier comprising (A) a diacylphosphatidylcholine, (B) cholesterol and/or a derivative thereof, and (C) an aliphatic primary amine is used as a nucleic acid delivery carrier to introduce the nucleic acid complex into a cell, the safety, the efficiency of intracellular delivery, and the persistence of the nucleic acid in the cell can be further improved.
