The present invention relates to a method and apparatus for partial etching or pattern etching using an electrolysis reaction, wherein, conventionally, there was the problem that an etching line could not be finely formed on a cell edge because of apparatus problems concerning alignment accuracy. The present invention provides a method and apparatus with which fine line etching is possible and which can form a line on a cell edge.Provided is a an electrolytic etching method of a substrate which is formed having a subject etching layer on a surface, having the steps of providing a fixed gap from a substrate end surface which is external to an end surface of the substrate for placing a working part of a working electrode and passing current between the substrate and the working electrode.