To provide a technique for providing sweetness to fermented beverage while enhancing the survival ratio of bifidobacteria when producing the fermented beverage using whey as a raw material.

The whey fermented beverage is produced by adding Bifidobacterium genus bacteria and Lactococcus genus bacteria to a fermented milk raw material containing a whey raw material whose solid content is 7 to 15 mass%, fermenting the same until pH of the fermented milk raw material becomes 5.0 or less, stopping fermentation and preparing fermented matter, thereafter adding sugar to the prepared fermented matter, and then homogenizing the same.