An object of the present invention is to provide a growth promoting agent and a life prolonging agent which are safer than a conventional one, and can be used for stable and effective production of animals including farm animals, domestic fowls and fishes/shellfishes, stable and effective cultivation of plants including vegetables, fruits and grains, stable and effective culture of microorganisms, and stable and effective cultivation of mushrooms. The present invention provides the growth promoting agent comprising a sugar alcohol, particularly erythritol, as an active ingredient and a life prolonging agent comprising a sugar alcohol, particularly erythritol, as an active ingredient.