To provide a cationic lipid usable for delivering a nucleic acid to cytoplasm. The cationic lipid of the present invention is, for example, a compound represented by formula (1) or a pharmacologically acceptable salt thereof. [In formula (1), L1 and L2 each independently represent a C3-10 alkylene group； R1 and R2 each independently represent a C4-24 alkyl or C4-24 alkenyl group； R3 represents a C1-3 alkyl group； and X1 represents a single bond or -CO-O-.].本發明提供一種能夠用於向細胞質傳遞核酸的陽離子性脂質。本發明的陽離子性脂質例如是下述式（1）所表示之化合物或其藥學上所容許之鹽。[化56][式中，L1及L2分別獨立地表示碳數3～10之伸烷基、R1及R2分別獨立地表示碳數4～24之烷基或碳數4～24之烯基，R3表示碳數1～3之烷基，X1表示單鍵或-CO-O-]。
