After fermenting several types of sake cake using the natto bacillus (Bacillus subtilis natto), it wasfound that a large amount of nattokinase or vitamin K₂ (menaquinone-7) was produced both throughstationary culture and liquid culture. Of ten types of sake cakes, or cakes made in the process of distilling, the sweet potato spiritproduced the largest amount of nattokinase. The amount of nattokinase produced from 100 g of drycultured substance was equivalent to over 168, 000 IU of urokinase. It was also found that menaquinone-7, which was not produced by using the HPLC method, was fermented up to a concentration of over31.73 mg. Considering the fact that nattokinase and vitamin K₂ are known to be the functional ingredientsproduced by the natto bacillus and have shown positive effects for certain conditions now keenlyfollowed by the public (senile dementia and osteoporosis), the fermentation technology applied this timemight prove to be a promising method for the effective use of sake cake made from distilled spirits, whose non-utilization and disposal has come to be deplored.