A RESURF-type NET is a suitable structure as a lateral switching device with a breakdown voltage of above 600 V for an inverter module which drives motors of an electric or hybrid automobile. In this study, 600 V RESURF-type JFETs were fabricated to investigate the operation and characteristics. The drift region between the drain and the source areas has a double RESURF structure to reduce the on-resistance. The width and the length of the channel are 200 mum and 10 mum, respectively. The distance between the drain and the gate areas, which is the drift length, is 15 mum. The saturation current of normally-off device is about 0.6 mA at a gate voltage of 3 V. The specific on-resistance is about 160 mOmegacm(2). The maximum breakdown voltage is 720 V.