To provide a means to occlude NOx suitably corresponding to a temperature distribution of a catalyst so as to purify more efficiently NOx.

A high-temperature region which reaches a high temperature during use adopts the combination of porous oxide having a high temperature, where the decomposition rate of carbonate becomes maximum, and NOx occluded material, and a low-temperature region which becomes relatively lower below the high temperature region during use adopts the combination of porous oxide having a low temperature, where the decomposition rate of carbonate becomes maximum, and NOx occluded material. At the high-temperature region, NOx can be occluded efficiently by contacting the high-temperature emission gas, and at the low-temperature region, NOx can be occluded efficiently by contacting the low-temperature emission gas to improve the NOx occlusion capability as an entire catalyst.