A disoxidant comprising metallic fine powder, water, filler, etc. which overcomes poor mixing properties due to the great specific gravity of the metallic fine powder without deteriorating cachet-loading properties. For the improvement in mixing properties, fine powder having about the same particle size as the metallic fine powder (not more than 100 mesh) is used as porous filler, in addition to coarse powder (not less than 100 mesh), with the ratio of the fine powder being 20 to 60 volume % and that of the coarse powder 80 to 40 volume %. In consideration of loading properties, water content is controlled to 20 to 90 % based on the amount of saturation-absorbed water for the sum of the fine powder and the coarse powder. Upon preparation, water is added to the powder to avoid aggregation of the fine powder. The volume ratio of the metallic fine powder to the filler mixture is 1/2 to 1/10, in accordance with the mixing properties, etc.