There is provided a hydrogelator that is capable of forming a hydrogel with an extremely small amount thereof over a liquid property range from acidic to alkaline, and a hydrogel having high environmental suitability, biocompatibility and biodegradability. A hydrogelator comprising a lipid peptide represented by Formula (1): (where R 1 represents an aliphatic group having 9 to 21 carbon atoms； R 2 , R 3 and R 4 independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atom(s) which may have a branched chain having 1 or 2 carbon atom(s), a phenylmethyl group or a -(CH 2 ) n -X group, and at least one of R 2 , R 3 and R 4 represents a -(CH 2 ) n -X group； n represents the number of 1 to 4； X represents an amino group, a guanidino group, a -CONH 2 group or a 5-membered ring, a 6-membered ring or a fused heterocyclic ring composed of a 5-membered ring and a 6-membered ring which may have 1 to 3 nitrogen atom(s)) or a salt thereof, and a hydrogel comprising the hydrogelator.
