GAS DIFFUSIVE ELECTRODE, ELECTROCONDUCTIVE ION CONDUCTOR, THEIR MANUFACTURING METHOD, AND ELECTROCHEMICAL DEVICE

Provided is a gas diffusion electrode, an electrically conductive ionic conductor which are capable of having electronic conductivity and ion conductivity, a method of producing the same, and an electrochemical device. An electrically conductive ionic conductor (5) comprises electrically conductive powder (1) having an ion conductive group (2) bonded thereto. The electrically conductive ionic conductor (5) is produced through bonding the ion conductive group (2) to the electrically conductive powder (1) by chemical treatment. A gas diffusion electrode comprises the electrically conductive ionic conductor (5), and the gas diffusion electrode is used as at least one of a positive electrode and a negative electrode in an electrochemical device such as a fuel cell.