The invention discloses an automatic tool setting method for an electric spark machine tool. A moving main shaft device of the electric spark machine tool comprises a large-Z-axis moving mechanism, an X-axis moving mechanism and a Y-axis moving mechanism; and a wire electrode is controlled by the moving main shaft device to move. According to the automatic tool setting method for the electric spark machine tool, operation is simple, the use is convenient, precision is high, and programming efficiency and machining efficiency of the electric spark machine tool are improved.