The present invention provides: a technique that makes it possible to introduce active components, in particular nucleic acids, into cells with excellent efficiency； and cationic lipids, etc. used in the technique. This compound or a salt thereof is represented by formula (I). In the formula, n is an integer of 2 to 5, R is a straight-chain C1-5 alkyl group, a straight-chain C7-11 alkenyl group, or a straight-chain C11 alkadienyl group, and wavy lines each independently represent a cis bond or a trans bond.
