A dishwasher includes a main body being generally of a box shape with an open front, a washer tub being slidably extracted from and retracted into the main body through the open front, the washer tub having an open top, and a covering member for blocking a gap to be opened between the washer tub and the main body when the washer tub is fully extracted from the main body. Therefore, when the washer tub is fully extracted from the main body, a rear end of an inner wall of the washer tub is located in front of a front end of the main body to open the gap and the opened gap is covered by the covering member.