The present invention relates to a vehicular air cleaner. It is an object to provide a DOR system which can utilize a purifying function of an ozone purifying element containing an activated carbon for a long period of time. As shown in A1 and A2 of FIG. 5, in the activated carbon at an initial state, an ozone purification rate is almost the same as the same wind velocity even when a temperature condition is different, even though the ozone purification rate is changed when the wind velocity is changed. After the endurance test, the ozone purification rate is increased even at the same wind velocity when the temperature becomes high as shown in B1 and B2 of FIG. 5. Thus, the temperature condition difference affects the ozone purification rate more as the deterioration o the activated carbon continues.