An object is to provide a lipid particle that is not positively charged at a pH of the body fluid (typically in the neutral range), and that enables efficient onset of the effect of a medicinal substance encapsulated in the lipid particle； and to provide a lipid for forming the lipid particle. The object is achieved by the phospholipid represented by formula (1), and a lipid particle containing the phospholipid:wherein R1 and R2 are identical or different, and represent a chain hydrocarbon group, m represents 1 or 2, n represents 1 or 2, and p represents an integer of 1 to 4.
