PURPOSE: To prepare fermented foods and cool and store them by providing a box on a door of a refrigerator for storing a container for accommodating fermented products, and a heater in the container accommodating the box for fermenting the fermented products in storage.

CONSTITUTION: A bracket 103 is disposed inside a door liner 102 of a refrigerator door, and a box 104 coupled and fixed to the bracket 103 for forming a storage space 106 for accommodating the container 105. A heater 113 is disposed in an inner case 108 where the container 105 is placed for containing yogurt for fermenting the yogurt stored in the container 105 accommodated in the box 104. As a result, fermentation foods are fermented and cooled and stored to prevent the fermentation foods from adversely affecting other foods in storage.