Sesamin and sesamolin, oil-soluble lignans of sesame seeds, exhibit antioxidative activity in vivo and show various metabolic functions. HPLC analysis to detect the sesamin and sesamolin contents was modified to easily screen hundreds of accessions. The sesamin and sesamolin contents changed with seed maturity and were highest in the capsules at 30 days after flowering, showing large varietal difference at that time. The sesamin and sesamolin contents are an inherited characteristic. “Gomazou” was selected from the progeny of a cross between “Toyama 016”, a large seed line from Peru and “H65”, a high-lignan-content line originating in south China. “Gomazou” stably contains roughly twice as much lignan as “Masekin”, a local Kanto-region cultivar with a good yield. A physiological activity test on fatty acid oxidation in the rat liver showed that “Gomazou” more profoundly affected lipid metabolism than the control variety, “Masekin”. A high-lignan-content sesame cultivar could promote new demand as a local speciality crop and revive domestic production in Japan.