There is provided a gelator that is capable of forming a gel by an extremely small amount of addition in a wide pH range from acidic to alkaline regions, and a gel having high environmental compatibility, biocompatibility, and biodegradability. A gelator comprising: a lipid peptide of Formula (1) wherein R 1 is a C 9-23 aliphatic group, R 2 is a hydrogen atom or a C 1-4 alkyl group optionally having a C 1-2 branched chain, R 3 is a -(CH 2 ) n -X group, n is a number from 1 to 4, and X is an amino group, a guanidino group, a -CONH 2 group, or a 5-membered ring optionally having 1 to 3 nitrogen atoms, a 6-membered ring optionally having 1 to 3 nitrogen atoms, or a fused heterocycle including a 5-membered ring and a 6-membered ring that optionally has 1 to 3 nitrogen atoms)； or a pharmaceutically usable salt of the lipid peptide.
