PURPOSE: To provide an ultraviolet laser beam generating device capable of generating a high-output ultraviolet laser beam at a place where the high-output ultraviolet laser beam is transmitted.

CONSTITUTION: An ultraviolet laser beam generating device is provided with a laser oscillator 1, an optical fiber 4 for making a laser beam 2 emitted from the oscillator 1 transmit, a first non-linear optical element 5 connected to the fiber 4 and converts the wavelength of the laser beam transmitted through the fiber 4, and a second non-linear optical element 6 connected to the element 5 and converts the wavelength of the laser beam emitted from the element 5. The element 5, which converts the wavelength of the laser beam, may be provided between the oscillator 1 and the fiber 4 and it is desirable to use a Q-switching YAG laser as the oscillator 1.