To provide a high-voltage semiconductor switch, capable of driving easily at a low drive circuit voltage and durable at high voltages easily.

A pulse transformer made up of a plurality of secondary windings 2, wound radially around an annular core 1, is located at almost the center of a substrate 10. A gate waveform shaping circuit 3 and a semiconductor switching element 4 are connected with each secondary winding 2. The semiconductor switch elements 4 are connected in series or in parallel.