Provided is an economical long-life insoluble anode capable of maintaining an anode function stably for a long time even if it is used in a part where severe consumption occurs to generate a cathodizing phenomenon, and also capable of reducing the amount of an electrocatalyst used as much as possible. To realize this, on the surface of a metal substrate 10 composed of a titanium plate, a porous layer 20 including a sintered body of a spherical titanium powder is formed as a base layer. An electrocatalyst layer 30 is formed from the surface of the porous layer 20 to its inside. A part of the electrocatalyst penetrates into the porous layer 20, which provides an incomparably stronger anchor effect than the case of a blast treatment. Even when parts exposed from the porous layer 20 are peeled off and dropped off, the anode function is maintained by the electrocatalyst left in the porous layer 20.