A generator of high-voltage rectangular pulses with a subnanosecond wave front is described. The generator includes a replaceable cable length, a switch, high-voltage connector and a load (attenuator). These elements form a single wave path, which enabled the duration of front pulse less than 0.5 ns to by obtained with the amplitude continuously variable up to 50 kV. The generator is designed to calibrate measuring transducer (pickups) for pulsed electric fields and to investigate electrical breakdown, the development of streamers, etc.