A process for hydrocarbon oil production which comprises: a first step in which a raw oil comprising oxygenic organic compounds and water-insoluble chlorine compounds is brought into contact with a hydrogenation catalyst constituted of a support comprising a porous inorganic oxide and at least one metal deposited on the support and selected from the elements in Group VIA and Group VIII of the periodic table, in the presence of hydrogen to yield a hydrocarbon oil and water in a vapor state through the deoxidizing hydrogenation of the oxygenic organic compounds and simultaneously convert the water-insoluble chlorine compounds into water-soluble chlorine compounds; a second step in which the reaction products obtained in the first step are kept so that the water is in a vapor state and are brought into contact with a water-soluble nitrogenous Br?nsted base compound having a boiling point at ordinary pressure of 100ºC or lower to thereby obtain a treated object; and a third step in which the treated object is cooled to or below a temperature at which the water in a vapor state liquefies, to form an aqueous phase containing the water-soluble chlorine compounds and the nitrogenous Br?nsted base compound, and the aqueous phase is then separated from the treated oil to obtain a product oil comprising the hydrocarbon oil.
