Current engineering production is characterized by ever-increasing requirements for the final quality of products. But high fabrication productivity is required in many cases as well. Another advantage is, of course, a beneficial economic efficiency of the production process. However, despite the advanced technical level of production and extensive knowledge in the field of electro-erosive machining, in many cases, the overall efficiency of the production process is based on the skills of operators. Besides, insufficiently experienced production operators sometimes still use the trial and error system, even today. A comprehensive set of information for selecting optimal conditions of the electric discharge machining process with the possibility of practical application in real conditions of practice is currently non-existent. The paper therefore describes the experimental measurements performed in order to optimize the quality of the machined surface with respect to electric energy consumption in the WEDM process. In contrast to current approaches, the solution of the issue relied on determining the relationship between the performance parameters of the process and its controllable output quality parameters so that they would be applicable to the conditions of real practice. It was found that with the reduction of discharge energy through individual WEDM operations, the quality indicators in terms of roughness parameters improve. However, on the other hand, reducing the discharge energy leads to a significant increase in the total electric energy consumption. Therefore, the aim of the performed optimization was to look for a suitable type of WEDM operation, in which a favourable value of the roughness of the eroded surface is achieved while maintaining favourable electric energy consumption.