Double-stranded ribonucleic acid for the adjuvant

The present invention is low toxicity and has a chain length which is suitable for indicating, and heating and cooling chain length be subjected to treatment is less likely to change double-stranded ribonucleic acid (dsRNA has high functionality in applications adjuvants such ) or a salt thereof; immune stimulant comprising the dsRNA or the like, adjuvant, or pharmaceuticals, etc.; and methods of producing such dsRNA or the like. The present invention, a weight average chain length of one ssRNA constituting the second strand the weight average chain length of 2 or more single-stranded ribonucleic acid that constitutes the first strand constituting the dsRNA (ssRNA) 1 / characterized by two or less.