A hydrogenation treatment catalyst is provided for heavy hydrocarbon oil, in which a hydrogenation-active component is supported on a silica-containing porous alumina carrier containing 0.1% to 1.5% by mass of silica based on the carrier. The total pore volume is 0.55 to 0.75 mL/g. Of the total volume of pores having a pore diameter of 3 to 30 nm (1) 30% to 45% have a pore diameter of 5 to 10 nm, (2) 50% to 65% have a pore diameter of 10 to 15 nm, and (3) the total volume of pores having a pore diameter in a range of ±1 nm from the average pore diameter is 25% or more. The total volume of pores having a pore diameter of 30 nm or more is 3% or less. The average pore diameter of pores having a pore diameter of 10 to 30 nm is 10.5 to 13 nm.