To provide a desulfurization method to separate and remove sulfur component from a raw oil such as light oil by electron ray irradiation and provide an apparatus for the desulfurization treatment.

The objective electron ray desulfurization apparatus is provided with a reaction chamber 12 holding a supplied raw oil 1 containing a sulfur compound and irradiating the oil with electron rays from above, an electron ray irradiation apparatus 23 to apply electron rays to the oil supplied to the reaction chamber and a precipitation tank 13 to store the irradiated liquid and precipitate the sulfur component of the liquid 2.