The present invention has an object to provide an external dermatological formulation having satisfactory blood flow-promoting effect, antiinflammatory effect, antibacterial effect, moisturizing effect, whitening effect, UV-absorbing effect, UV-scattering effect, antioxidant effect, hair growing effect, hair nourishing effect, emusifying effect, astringent effect, wrinkle-reducing effect, cell-activating effect and / or transdermal absorption-promoting effect with a satisfactory safety and skin feeling; The object is solved by providing an external dermatological formulation comprising a saccharide derivative of α,α-trehalose and one or more members selected from substances having any one of blood flow-promoting effect, antiinflammatory effect, antibacterial effect, moisturizing effect, whitening effect, UV-absorbing effect, UV-scattering effect, antioxidant effect, hair growing efect, hair nourishing effect, emulsifying effect, astringent effect, wrinkle-reducing effect, cell-activating effect and transdermal absorption-promoting effect.