Abstract: Disclosed is a device for penetrating a skin active agent to the human body via the skin by the use of an ultrasound applying apparatus which applies ultrasound to the human body via the skin, comprising: (1) composition comprising: (a) safe and effective amount of the skin active agent; (b) a viscosifying agent that provides the composition a viscosity of from about 1,000 mPas to about 1,000,000 mPas; (c) from about 0.1% to about 30% of a water-soluble humectant; and (d) an aqueous carrier; wherein the composition is substantially free of surfactants; and (2) the ultrasound applying apparatus comprising: (e) an application element for applying to the skin ultrasound at a frequency of from about 3 MHz to about 10 MHz and an intensity of from about 0.1 W/cm2 to about 2 W/cm2; and (f) a control element for controlling application conditions of the application element.