The present invention relates to a Mn-added titania carrier obtained by adding a Mn salt to amorphous titania and baking the titania. The invention also relates to an NOx adsorbent comprising the above-mentioned titania carrier and adsorbing components comprising oxides of Ru and/or Ce supported on the carrier. The invention also relates to an NOx adsorbent comprising the above-mentioned titania carrier and adsorbing components comprising oxides of Ru and/or Ce and an oxide of at least one metal among Ag, Cu and Mn supported on the carrier. The NOx adsorbents embodying the invention are effectively used for efficiently adsorbing and removing NOx from gases which contain much moisture and low-concentration, for example, a few ppm NOx such as gases discharged by ventilation from highway tunnels.