The present invention provides a compound represented by formula (I), which is usable as a cationic lipid facilitating the introduction of a nucleic acid into a cell, or the like, and a composition, or the like, containing the compound.本發明提供一種式(I)所表示之化合物、及含有該化合物之組合物等,該化合物可用作使向細胞內等導入核酸變得容易之陽離子性脂質。