Charged particle emission gun and charged particle ray apparatus

Provided is a charged particle emission gun with which chip cleaning can be performed for a long period without stopping operation of the charged particle emission gun and without heating the chip. The charged particle emission gun is provided with: a cleaning photo-irradiation device which generates ultraviolet light or infrared light that is used to irradiate a chip; and an optical fibre which guides the ultraviolet light or infrared light onto the chip. The cleaning photo-irradiation device generates ultraviolet light or infrared light of a prescribed wavelength and intensity in order to remove molecules adsorbed to the chip by photo-stimulated removal, or in order to remove molecules adsorbed to the chip by photo-stimulated removal and ionise the removed molecules.