A vacuum ultraviolet light source for generating a pulse discharge in a low pressure gas and extracting ultraviolet light from a plasma created in that discharge, is disclosed which comprises a discharge space P, a plate-like anode located in the discharge space, a plurality of hollow cathodes located in the discharge space in an opposed, spaced-apart relation to the anode, auxiliary electrodes provided in an inside space of the hollow cathode in a state shielded from the hollow cathode, means which, while maintaining a pressure in the discharge space constant, flows a gas along a route in the discharge space after passing through an inner space in each hollow cathode, a power supply for supplying an electric power for generating a main discharge across the hollow cathode and the anode after a pre-discharge is produced across each hollow cathode and the anode, and ultraviolet extracting means for extracting ultraviolet light radiated from a plasma which is produced by a discharge in the discharge space.