A transdermally absorbable base material including: a lipid peptide compound including at least one of compound of Formula (1) below and the similar compounds or pharmaceutically usable salts thereof； a surfactant； a specific polyhydric alcohol； a fatty acid； and water,wherein R1 is a C9-23 aliphatic group； R2 is a hydrogen atom or a C1-4 alkyl group that optionally has a branched chain having a carbon atom number of 1 or 2； R3 is a —(CH2)n—X group； n is a number of 1 to 4； and X is amino group, guanidino group, —CONH2 group, or a 5-membered cyclic group optionally having 1 to 3 nitrogen atoms, a 6-membered cyclic group optionally having 1 to 3 nitrogen atoms, or a condensed heterocyclic group constituted by a 5-membered cyclic group and a 6-membered cyclic group which optionally have 1 to 3 nitrogen atoms.
