To provide a hydrotreating method which comprises subjecting a heavy hydrocarbon oil containing a large quantity of impurities comprising e.g. sulfur, residual carbon, a metal, nitrogen and an asphaltene, particularly a heavy oil containing a large quantity of heavy vacuum residual oil to hydrotreating to a high degree while removing it appropriately and which is excellent in reducing or controlling the amount of a sediment formed.

This method of hydrotreating of a heavy hydrocarbon oil comprises: bringing a heavy hydrocarbon oil into contact with a catalyst (1) having a specified specific surface area and pore distribution in the presence of hydrogen in a first reactor filled with the catalyst (1) to effect first-stage hydrotreating; and bringing the hydrotreated oil obtained in the first stage into contact with catalysts (2a) and (2b) each having a specified specific surface area and pore distribution in the presence of hydrogen in a second reactor filled with the catalysts (2a) and (2b) to effect second-stage hydrotreating.