Disclosed is a novel agent for improving the viability of a lactic acid bacterium, which has an excellent effect of improving the viability of a lactic acid bacterium, has no adverse influence on the flavor of a product, and can be produced at low cost. The agent is characterized by comprising manganese as an active ingredient. In the agent, manganese may be used in the form of a manganese-containing material. Manganese is preferably contained in a final product in an amount of 5 μg/100 g or more.