[Problem] The present invention addresses the problem of providing a composition for preventing or improving the deposition of fat in the liver, irrespective of an alcohol intake history of a level such that alcohol intake is not the cause of liver disease. [Solution] The inventors discovered that glutathione has an effect for preventing or improving fat deposition in the liver that is not caused by alcohol, thereby perfecting the present invention. In particular, the present invention is effective when nonalcoholic fatty liver disease is not treated early or when no treatment is conducted for another disease.