This paper is concerned with the shock wave visualization using an electric discharge. In the previous discharge method, point-point electrodes had been used to generate electric discharges. The shape of the electric discharges was a column and only one point across a shock wave could be measured. Therefore, many discharge columus had to be generated to obtain the whole shock shape. However, in this method using point-line electrodes, a plain discharge is generated and the whole shock shape can be visualized by one plain discharge. The experimental conditions for making the plain discharge by using pointline electrodes have been investigated in preliminary experiments. The shock shape around a semicone body with delta wing can be visualized by utilizing the experimental results.