[Problem] To provide a bactericidal composition for bacterial skin disease against which it is difficult for bacteria that cause bacterial skin disease to acquire drug resistance.[Solution] A bactericidal composition for bacterial skin disease that is characterized by including silver iodide in the form of nanoparticles having a particle size of 1-100 nm, inclusive, iodide ions, a water-soluble polymer, and an organic acid having a carboxyl group, and/or a salt of said acid, wherein the molar ratio of silver to iodide ions in the silver iodide is 1:1-1:1000.