A hydrocarbon oxidation catalyst according to the present invention includes a catalyst carrier containing zirconia; and an active metal supported on the catalyst carrier. The zirconia contains a monoclinic zirconia phase and a tetragonal zirconia phase. In the zirconia, a ratio of a peak intensity of the tetragonal zirconia phase to a peak intensity of the monoclinic zirconia phase in an X-ray diffraction measurement is 0.005 or more and less than 0.8, and the monoclinic zirconia phase has a crystallite diameter of 35Å or more and 115Å or less.