The present invention provides an electrochemical electrode wherein transition metal (nickel) nanoparticles are used to form an active layer having a large surface area without using a conductive support while maintaining dispersibility and stability, and a method for producing the same. The present invention provides an electrochemical electrode having a conductive substrate and an active layer formed on the conductive substrate, wherein (1) the active layer has a nickel-containing nanostructured material having a dendritic structure formed by agglomerating a plurality of primary particles, and (2) each primary particle has a core and a shell surrounding the core wherein the core is formed of a nickel nanocrystal and the shell is formed of a nickel oxide film; and the present invention also provides a method for producing such an electrochemical electrode comprising: Step 1 of obtaining nickel nanocrystal particles, Step 2 of obtaining primary particles by forming a nickel oxide film on the surface of each nickel nanocrystal particle, and Step 3 of forming a dendritic structure by agglomerating a plurality of the primary particles by depositing the primary particles substantially perpendicular to a conductive substrate.