A synbiotic food composition is a food composition for promoting the active intestinal growth of Lactobacillus sp. lactic acid bacterium, containing lactic acid bacteria and tagatose as a source of nutrients for the bacteria strain. More particularly, The synbiotic food composition contains a Lactobacillus casei strain or Lactobacillus rhamnosus strain as a probiotic, and tagatose as a prebiotic.