NOVELTY - An electrode has a transparent conductive layer, a current collection wire arranged on the conductive layer and extended in direction (X), several current collection wires arranged at intervals along direction (Y) perpendicular to direction (X), and a photocatalyst layer formed in region containing at least one portion of current collection line region, which is located between two adjacent current collection wires. The electrode satisfies specific relation relating sheet resistance value, voltage loss and electric current value.    USE - Electrode used in gas production apparatus for producing hydrogen gas and oxygen gas using photocatalyst from water-containing electrolyte solution.    ADVANTAGE - The electrode effectively contributes to decomposition of water in gas production apparatus.    DETAILED DESCRIPTION - An electrode has a transparent conductive layer, a current collection wire arranged on the conductive layer and extended in direction (X), several current collection wires arranged at intervals along direction (Y) perpendicular to direction (X), and a photocatalyst layer formed in region containing at least one portion of current collection line region, which is located between two adjacent current collection wires. The electrode is projected in direction perpendicular to conductive layer among the regions on conductive layer. The length of current collection wire along direction (X) is L (m). The distance between current collection wire, which forms one end of several wires arranged along direction (Y), and current collection wires, which form the end at the side of opposite direction is set to width W (m). The distance between two adjacent current collection wires along direction (Y) is set to distance D (m). The sheet resistance value of transparent conductive layer is set to R ( Omega /square). The reference value of electric current value collected by current collection wires is set to I(A). The target value of improvement value of voltage loss by using current collection wires measured from reference voltage loss, which is voltage loss by conductive layer is set to Delta (V). The electrode satisfies relation given by: D less than L-((2x Wx ( Delta (V)))/(I/asteriskR)).