An amphiphilic compound of long-chain amide derivative bearing hydroxy groups as the terminal groups possessed an ambidextrous gel property, i.e., it made gels in both organic solvents and in aqueous solutions. Further, sol-gel transition of the hydrogel was able to be controlled reversibly by pH. Small-angle X-ray scattering and FT-IR measurements showed that the main interaction of the aggregate formation was hydrogen bonding between the amide groups and that the aggregates had lamellar structures in both the organogel and the hydrogel.