Provided is a refrigerator including an adiabatic space formed on an inner surface of a chilling chamber door and an ice machine disposed inside the adiabatic space, thereby enabling a more efficient usage of an inner space of the refrigerator. Also, the present invention provides a cooling air passage structure of a refrigerator for properly supplying cooling air for freezing to an inside of the refrigerator having an ice machine disposed on an inner surface of a chilling chamber door.