An alumina support for a catalyst for a gas-phase reaction that increases the catalytic activity and allows a reduction in by-product yield, and a catalyst for a gas-phase reaction that is a metal compound supported on the alumina support are provided. The alumina support for a catalyst for a gas-phase reaction has a tubular shape with at least one hollow through hole and a BET specific surface area of 140 to 280 m2/g. In this alumina support, a volume (total pore volume) of pores with a diameter of not less than 15 nm and not more than 20000 nm is 0.04 to 0.15 cm3/g, and a volume of pores with a diameter of not less than 1000 nm and not more than 20000 nm is 0.02 cm3/g or less, as measured by the mercury intrusion technique, and a tapped bulk density is 620 to 780 g/L.