PROBLEM TO BE SOLVED: To facilitate the operation and to improve the operability in preparation for washing and treatment after the washing, etc., by separating a washing tub from a body frame on the drive side to be detachably mounted in a washing device for washing clothes stored in the washing tub. SOLUTION: The washing device consists of a drive side base 7 with a built-in rotary drive device 8 and the washing tub 1 to be mounted detachably on the upper surface of the drive side base 7 whose top has an opening. The washing tub 1 has an agitator 2 disposed rotatably on the inner bottom for agitating clothes. The agitator 2 is mounted on the upper end of a shaft part 5 piercing the bottom of the washing tub 1, and a first transmission coupling 6 is mounted on the lower end of the shaft part 5 for transmitting the rotation drive. The drive side base 7 has a second transmission coupling 10 rotating connected with the rotary drive device 8. When the washing tub 1 is mounted on the upper surface of the drive side base 7, the first transmission coupling 6 and the second transmission coupling 10 are jointed with each other.