A refrigerator comprising: a cabinet configured to define a first storage region in which food is stored; a door rotatably installed to the cabinet via a first hinge member to open or close the first storage region; a container configured to define a second storage region, the second storage region being received in the first storage region, the container being rotatably connected to the door via a second hinge member; a gasket provided to an inner rim portion of the door to prevent leakage of cold air through a gap between a front surface portion of the cabinet and the inner rim portion of the door, when the door is closed and the container is placed in the first storage region; a latch member (130, 1610) installed to the container; and a fastening device (600, 1600) provided at the door, the fastening device (600, 1600) being caught by the latch member (130, 1610) to selectively couple the door and the container to each other, wherein the fastening device (600, l600) includes: - a hook configured to be caught and fixed by the latch member (130, 1610), the hook being located in the region surrounded by the gasket, - an operating unit having a lever configured to be pushed by a user, and characterized in that the fastening device (600, 1600) further includes: a seal configured to prevent outward movement of cold air through the fastening device (600, 1600) in a state in which the door and the container are coupled to each other; - a first link and a second link configured to transfer displacement generated by the lever, wherein the hook is pivotally rotatably installed and the second link pivotally rotates the hook; and wherein the first link extends in the width direction of the door, and the second link extends in a depth direction of the door, and the first link and the second link have movement directions perpendicular to each other a cabinet configured to define a first storage region in which food is stored; a door rotatably installed to the cabinet via a first hinge member to open or close the first storage region; a container configured to define a second storage region, the second storage region being received in the first storage region, the container being rotatably connected to the door via a second hinge member; a gasket provided to an inner rim portion of the door to prevent leakage of cold air through a gap between a front surface portion of the cabinet and the inner rim portion of the door, when the door is closed and the container is placed in the first storage region; a latch member (130, 1610) installed to the container; and a fastening device (600, 1600) provided at the door, the fastening device (600, 1600) being caught by the latch member (130, 1610) to selectively couple the door and the container to each other, wherein the fastening device (600, l600) includes: - a hook configured to be caught and fixed by the latch member (130, 1610), the hook being located in the region surrounded by the gasket, - an operating unit having a lever configured to be pushed by a user, and - a hook configured to be caught and fixed by the latch member (130, 1610), the hook being located in the region surrounded by the gasket, - an operating unit having a lever configured to be pushed by a user, and a seal configured to prevent outward movement of cold air through the fastening device (600, 1600) in a state in which the door and the container are coupled to each other; - a first link and a second link configured to transfer displacement generated by the lever, wherein the hook is pivotally rotatably installed and the second link pivotally rotates the hook; and - a first link and a second link configured to transfer displacement generated by the lever, wherein the hook is pivotally rotatably installed and the second link pivotally rotates the hook; and wherein the first link extends in the width direction of the door, and the second link extends in a depth direction of the door, and the first link and the second link have movement directions perpendicular to each other