The present invention provides a disposable diaper and a diaper cover having inner seal parts which can prevent body wastes from leaking out of both sides of the diaper or both sides of the diaper cover. It is provided with a liquid permeable topsheet 2, a liquid impermeable backsheet 3, an absorber 4 which absorbs and holds liquid and is interposed between the topsheet and the backsheet, a belt 7 to which one end of the topsheet and backsheet is fixed, a connection 8 which is formed at one end of the belt and is connected with the other end of the belt, inner seal parts 5 and 6 provided at both sides of the topsheet in the lengthwise direction and arranged to be stretchable in the lengthwise direction, and fastening portions 5c and 6c fastened to the belt and provided at front ends of the inner seal parts.
