To obtain an acidic dairy food excellent in long-term preservability by including a pectin hydrate so as to prevent the lactoprotein's coagulation and precipitation without causing excessive thickening or impairing the food flavor.

This acidic dairy food comprises a milk component such as cow milk, powdered skim milk or whole milk powder, and also contains a pectin hydrate such as high-methoxylpectin pref. at ≥0.4 wt.% calculated as pectin concentration; wherein it is preferable that the pectin hydrate and the lactoprotein derived from the milk component are joined together to form a conjugate whose particle size is ≤2 μm.