An overhead door with a pair of stays and a respective stay holding tension springs. Each of the stays is rotatably fitted to the inner surface of a corresponding lateral wall of a cabinet main body by way of a rotary shaft and have their front end pivotably secured to the door at a position close to the lower edge of the door. Each of the stay holding tension springs are so arranged that each of them is hooked at an end to a position located upward and forward relative to the corresponding rotary shaft on the inner surface of the related lateral wall of the cabinet main body and at the opposite end to a middle point of the corresponding stay.