A method of measuring with which it is possible to measure with a high accuracy a gas introducing hole provided in an electrode for a plasma etching device, and to provide an electrode provided with a highly-accurate gas introducing hole is described. This method is provided to penetrate through in the thickness direction of a base material of the electrode for the plasma etching device, provided with: a step of radiating light toward the gas introducing hole from one surface side of the substrate; a step of acquiring a two-dimensional image of light which has passed through the gas introducing hole to the other surface side of the substrate; and a step of measuring at least one of the diameter, the inner wall surface roughness, and the degree of verticality of the gas introducing hole, on the basis of the two dimensional image.