A purification catalyst and a gas-purifying apparatus are provided which are capable of sufficiently purifying a gas subject to treatment at low temperatures. The purification catalyst includes ZrO2 having a specific surface area of 50 m2/g or less and a monoclinic crystal system. The gas-purifying apparatus includes the aforementioned purification catalyst as a first purification catalyst, and a second purification catalyst containing Mn as a major component and disposed upstream of the first purification catalyst.