An apparatus to automatically close a refrigerator door when the door is opened at a predetermined angle or less. The apparatus includes a hinge mechanism having a first hinge shaft provided at the door, which allows the door to be coupled to a refrigerator cabinet and allows the door to be rotated about the hinge shaft, a tension spring provided at the refrigerator cabinet to apply the door with a tension force for closing the door, and a unit to asborb shock generated when the door is closed by the tension spring, and the a unit to absorb shock includes a housing coupled to the cabinet, and a movable shaft which is received in the housing at its one end and connected to the door at the other end to be linearly moved in the housing, and wherein the tension spring is connected to the cabinet at its one end and connected to the movable shaft at the other end to apply the door with a tension force of closing the door. Thus, when the door is opened at an angle of 90 degrees or less, the door is automatically closed and when the door is opened at an angle greater than 90 degrees, the door remains in its position. Accordingly, use of the refrigerator is convenient, and the maximum rotation angle of the door can be controlled according to a user's desire.