PURPOSE: To provide a transparent, protein-contg. soft drink free from bitter taste, gustatoriness and offensive odor.

CONSTITUTION: The objective soft drink containing protein hydrolysate (through enzymolysis) having the following characteristics: (1) free from offensive odor unique to protein when 1wt.% aqueous solution thereof is put to sensory test; (2) free from bitter taste and gustatoriness for 5wt.% aqueous solution thereof; (3) developing no precipitate and suspension when boiled; (4) absorbances A720 and A440 for 5wt.% aqueous solution thereof are ≥0.01 and ≥0.5, respectively; (5) nothing left on a membrane filter when put to filtration test for foreign substances; and (6) free amino acid content of the whole protein hydrolysate is ≤5wt.%.