Lipid tripeptide-based hydrogelator and hydrogel

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 R¹ represents an aliphatic group having 9 to 21 carbon atoms;
R², R³ and R⁴ 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 —(CH₂)_n—X group, and at least one of R², R³ and R⁴ represents a —(CH₂)_n—X group; n represents the number of 1 to 4; X represents an amino group, a guanidino group, a —CONH₂ 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.