A refrigerator comprising: a cabinet configured to define an exterior boundary of the refrigerator; a first storage chamber defined by interior walls of the cabinet and configured to store food stuffs; a first door configured to open and close the first storage chamber and having an opening; a second storage chamber that is smaller than the first storage chamber and is defined at a rear side of the first door, and that is configured to enable access to food stuffs therein through the opening of the first door, while the first door remains closed; a second door, coupled to an outer surface of the first door, configured to open and close the opening of the first door; a first connection member of which one end is coupled to an upper surface of the cabinet and the other end is coupled to an upper surface of the second door; a second connection member of which one end is coupled to an upper surface of the first door and the other end is coupled to the upper surface of the second door; a rotational shaft coupled to the upper surface of the second door by passing through the other end of the first connection member and the other end of the second connection member, wherein a rotation direction of the second door is identical to the rotation direction of the first door, wherein the first door includes a securing part stepped toward the cabinet and configured to secure the second door therein, wherein an upper portion of the securing part of the first door is exposed such that the upper surfaces of the first and second doors (20, 30) are at an identical level, wherein a thickness of the second door is identical to a thickness of the securing part and a width of the second door is identical to a width of the first door, wherein a first recess is recessed inwardly at a predetermined portion of the first door adjacent to a lower surface of the second door, and wherein the first door comprises a second recess which is recessed downwardly from the first recess configured to be used as a door handle to the first door. a cabinet configured to define an exterior boundary of the refrigerator; a first storage chamber defined by interior walls of the cabinet and configured to store food stuffs; a first door configured to open and close the first storage chamber and having an opening; a second storage chamber that is smaller than the first storage chamber and is defined at a rear side of the first door, and that is configured to enable access to food stuffs therein through the opening of the first door, while the first door remains closed; a second door, coupled to an outer surface of the first door, configured to open and close the opening of the first door; a first connection member of which one end is coupled to an upper surface of the cabinet and the other end is coupled to an upper surface of the second door; a second connection member of which one end is coupled to an upper surface of the first door and the other end is coupled to the upper surface of the second door; a rotational shaft coupled to the upper surface of the second door by passing through the other end of the first connection member and the other end of the second connection member, wherein a rotation direction of the second door is identical to the rotation direction of the first door, wherein the first door includes a securing part stepped toward the cabinet and configured to secure the second door therein, wherein an upper portion of the securing part of the first door is exposed such that the upper surfaces of the first and second doors (20, 30) are at an identical level, wherein a thickness of the second door is identical to a thickness of the securing part and a width of the second door is identical to a width of the first door, wherein a first recess is recessed inwardly at a predetermined portion of the first door adjacent to a lower surface of the second door, and wherein the first door comprises a second recess which is recessed downwardly from the first recess configured to be used as a door handle to the first door.