The tub projecting parts 18 are constituted by forming first cross-sections vertical relative to the axial direction of the washing and spin-drying tub 15 to be triangular, and forming the second cross sections perpendicularly crossed with the first cross-sections and along the axial direction of the washing and spin-drying tub 15 to be circular arcuate. この槽凸部18は、洗濯兼脱水槽15の軸方向に対して垂直な第1の断面が三角状をなし、第1の断面と直交して洗濯兼脱水槽15の軸方向に沿った第2の断面が円弧状に形成されている。 - 特許庁