The present invention aims to provide reduced coenzyme Q10, which is useful as food, food with nutrient function claims, food for specified health use, nutritional supplement, nutritional product, animal drug, drink, feed, cosmetic, pharmaceutical product, therapeutic drug, prophylactic drug and the like, and a production method of reduced coenzyme Q10. The present invention provides a production method of reduced coenzyme Q10, which includes reducing oxidized coenzyme Q10 with ascorbic acid or its analogue(s) as a reducing agent in a water-containing organic solvent at not more than pH 5. Using the method, the reaction time can be drastically shortened even without adding a basic substance and the like, and unpreferable side reactions can be minimized. Therefore, reduced coenzyme Q10 with high quality can be produced.