An electrochemical device includes an electrolyte membrane, an anode disposed on a first main surface of the electrolyte membrane, a cathode disposed on a second main surface of the electrolyte membrane, an anode separator disposed on the anode, and a cathode separator disposed on the cathode. At least one of the anode separator or the cathode separator includes a metal substrate sheet and a conductive layer disposed on the metal substrate sheet and containing a metal oxide and a metal hydroxide.