[Problem] A valine, isoleucine, leucine mixture wich is excellent in the reduction of bitter taste and improved dissolution speed is provided. [Solving Means] The above problem is solved by a solid solution composed of three amino acids of valine, isoleucine, leucine, and a solid solution composed of these and at least one of acid selected from the group consisting of neutral aliphatic amino acid, neutral hydroxy amino acid, neutral acid amide amino acid, acidic amino acid, basic amino acid, hydroxy acid.
