A generator of high-voltage pulses of nanosecond duration with a subnanosecond rise time is described. The generator contains a nanosecond-pulse shaper based on an assembly of drift step-recovery diodes (DSRDs) connected in series and a sharpening switch based on an assembly of deep-level dynistors (DLDs) connected in series. The results of tests of this generator at a pulse repetition rate of 100 Hz are presented. Voltage pulses with an amplitude of 20 kV, a rise time of 0.3 ns, and a duration of 10 ns are formed across a load with a resistance of 50 Ω.