An agent for preventing or ameliorating skin aging, which exhibits a more excellent effect on the suppression of formation, or the amelioration, of wrinkles on the skin or sagging skin. An agent for preventing or ameliorating skin aging, containing triterpenoid saponins represented by the following formula (1) as an active ingredient, wherein at least one of R1 and R2 is a tigloyl group and the other represents a tigloyl group or an angeloyl group; R3 represents a methyl group or a hydroxymethyl group; and R4 represents Glc, Xyl or Gal.