This invention relates to a nucleic acid complex with low toxicity and high safety that can maintain a nucleic acid molecule capable of RNA interference or translation inhibition, 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 maintain a nucleic acid in a cell can be obtained by forming a complex using a nucleic acid molecule capable of RNA interference or translation inhibition and a cycloamirose. Further, by using a carrier comprising (A) a diacylphosphatidylcholine, (B) cholesterol and/or a derivative thereof, and (C) an aliphatic primary amine as a nucleic acid delivery carrier to introduce the nucleic acid complex into a cell, the safety, efficiency of intracellular delivery, and persistence of the nucleic acid in the cell can be further improved.
