To establish the optimal fermentation periods in the manufacture of mushroom fermentation foods using sugar, changes of quality characteristics of the mushrooms fermentation broth were investigated with changes of enzyme activity and physiological functionality during fermentation. Viscosity, L value (lightness), a value (redness) and b value (yellowness) were significantly decreased after 3 months of fermentation and after that, increased. In sensory evaluation test, unique flavors and tastes of mushrooms in the fermented broth were decreased during fermentation, whereas the other tastes and flavors were gradually increased. Overall acceptability was the highest in the 3 months of fermentation broth. ${alpha}-Amylase$ activities of the fermented broth were significantly increased to 1 month of fermentation, however invertase and cellulose activities were low or not detected in the fermented broth. Antioxidant activities were the highest in 4 months of fermentation and after that, decreased. Tyrosinase inhibitory activities were high in all samples and they were not changed during fermentation. SOD-like activity was high in the fermentation broth of Flammulina velutipes and it was also not changed during fermentation. In conclusion, optimal fermentation periods in the manufacture of mushroom fermentation foods using sugar was 3 or 4 months.