PURPOSE: To economically obtain in high yield stably over a long period low- impurity vacuum-distilled desulfurized light oil and deasphalted oil.

CONSTITUTION: This hydrogenation treatment process is made up of the following consecutive three processes: (a) asphaltene-contg. heavy hydrocarbon oil is hydrogenated in the presence of a relevant catalyst under such conditions that the decomposition rate of the asphaltene fall between 40 and 75wt.%, (b) the resultant oil is vacuum-distilled and separated into vacuum-distilled light oil and vacuum-distilled residual oil, and the former coil is recovered, and (c) the vacuum-distilled residual coil is deasphalted with a solvent and separated into deasphalted oil and asphaltene-contg. deasphalted residues, and the deasphalted oil is recovered.