The present invention provides a core-shell structure having high skin permeability. The core-shell structure includes a core portion containing a hydrophilic drug having a molecular weight of 400 or more； and a shell portion containing a surfactant, and the core portion is a solid, the hydrophilic drug has a water-octanol partition coefficient of -3 or more and 6 or less, the surfactant has an alkyl group or an alkenyl group having 10 to 20 carbon atoms, and a mass ratio between the hydrophilic drug and the surfactant (hydrophilic drug:surfactant) is 1:5 to 1:20.
