The present invention provides a dermal composition comprising a polymeric reversed micelle that allows a water-soluble drug to be efficiently encapsulated and that is superior in percutaneous absorptiveness and very safe, and provides a method that can produce the composition in simple steps. The dermal composition comprises a polymeric reversed micelle composed of an amphipathic polymer having a hydrophilic segment and a hydrophobic segment, wherein the polymeric reversed micelle has a configuration in which the hydrophilic segment is the core and the hydrophobic segment is the shell, and a water-soluble drug is encapsulated therein. The composition can be produced by blending an oil phase comprising the amphipathic polymer in an oily base agent with an aqueous phase comprising the water-soluble drug in an aqueous solvent, or by blending an oily base agent with an aqueous phase comprising the amphipathic polymer and the water-soluble drug in an aqueous solvent.