The present invention provides a double-stranded ribonucleic acid (dsRNA) having a chain length suitable for simultaneously showing low toxicity and high function in the use of adjuvant and the like, and resisting variation of chain length even when subjected to a heating and cooling treatment, or a salt thereof an immune potentiator, adjuvant, pharmaceutical product and the like containing the dsRNA and the like and a production method of such dsRNA and the like.The present invention is characterized in that the weight average chain length of two or more single-stranded ribonucleic acids (ssRNAs) constituting the first chain constituting dsRNA is set to not more than 1/2 to the weight average chain length of one ssRNA constituting the second chain.
