This disclosure provides a method for manufacturing an optical proximity correction (OPC) mask, the method using an electron beam, and an OPC mask manufactured using the method. In the method, a mask is placed on a holder and a mask pattern for a photolithography process formed on the mask by illuminating the mask with an electron beam. A desired pattern is formed on the mask and an amended pattern is formed in consideration of a Kennel Effect by changing the size of the electron beam in a portion of the desired pattern where the Kennel Effect occurs. With the method, an amended pattern is made by defocusing an electron beam to change the size of the electron beam. Accordingly, an additional large amended pattern file is not required and the CPU memory for an apparatus using this method is not overloaded. This method thereby simplifies the process of manufacturing an OPC mask and complicated amended patterns are easily produced.