A door deceleration mechanism, which prevents the doors especially in built-in fridges and the like from closing too fast, essentially comprising - at least one fixed bracket which is fixed on the volume on which the door is closed, - at least one upper bracket which is fixed on the door and moves together with the door, - at least one first arm which is connected on the fixed bracket from one side, and which can freely rotate centered around the connection point, - at least one second arm which is connected on the upper bracket from one side and on the first arm from the other side, which can freely rotate from the connection points of the first arm and the upper bracket, and - at least one third arm which is connected on the upper bracket from one side and on the part of the first arm that is closer to the fixed bracket, which can freely rotate from the connection points of the first arm and the upper bracket, - at least one guide arm which is connected to the fixed bracket from one side and to the third arm from the other side, which can freely rotate through the connection points, and which guides the third arm during the opening and closing movement of the door, - at least one pin which is fixed on the second arm. and characterized in - at least one damping arm which is connected on the third arm from one side such that it can rotate freely and to the second arm by the pin passing inside a linear channel shaped slot provided on said damping arm from the other side, which makes rotary motion centered around the third arm during the closing movement of the door, and which decelerates the closing movement of the cover with a flexing motion after the movement of the slot towards the pin ends. - at least one fixed bracket which is fixed on the volume on which the door is closed, - at least one upper bracket which is fixed on the door and moves together with the door, - at least one first arm which is connected on the fixed bracket from one side, and which can freely rotate centered around the connection point, - at least one second arm which is connected on the upper bracket from one side and on the first arm from the other side, which can freely rotate from the connection points of the first arm and the upper bracket, and - at least one third arm which is connected on the upper bracket from one side and on the part of the first arm that is closer to the fixed bracket, which can freely rotate from the connection points of the first arm and the upper bracket, - at least one guide arm which is connected to the fixed bracket from one side and to the third arm from the other side, which can freely rotate through the connection points, and which guides the third arm during the opening and closing movement of the door, - at least one pin which is fixed on the second arm. and characterized in - at least one damping arm which is connected on the third arm from one side such that it can rotate freely and to the second arm by the pin passing inside a linear channel shaped slot provided on said damping arm from the other side, which makes rotary motion centered around the third arm during the closing movement of the door, and which decelerates the closing movement of the cover with a flexing motion after the movement of the slot towards the pin ends.