There is provided a lipid peptide 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 lipid peptide represented by Formula (1): where R1 represents an aliphatic group having 9 to 23 carbon atoms; R2, R3, R4 and R5 independently represent a hydrogen atom, an alkyl group having 1 to 7 carbon atom(s) which optionally has a branched chain having 1 to 3 carbon atom(s), a phenylmethyl group, a phenylethyl group or a —(CH2)n—X group, and at least one of R2, R3, R4 and R5 represents a —(CH2)n—X group; n represents the number of 1 to 4; X represents 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 optionally have 1 to 3 nitrogen atom(s); and m represents 1 or 2, and a hydrogel comprising the lipid peptide.