To achieve an accurate washing by a method wherein a plurality of water and detergent injection nozzles arranged on the sides of a bathtub and a washing field of a bath room are turned or moved to inject water and a detergent in a line so that the water and the detergent penetrate thoroughly.

Two water injection nozzles 9 are arranged at an interval between the side of a bathtub 4 and a washing field 5 striding a crossover part 10 to allow the washing of rising surfaces 11 and 12 of a bathtub 4. Likewise, detergent injection nozzles 13 are arranged at the same position at an interval below the water injection nozzles. The water injection nozzles 9 and the detergent injection nozzles 13 form an injection port 14 of a vertical groove so as to inject water and the detergent in a line while the nozzle parts are turned so that the water and the detergent penetrate all through a bathtub. When a solenoid valve is opened to inject water while a motor is operated, the water moves rotating being injected in a line from the injection port 14 to wash a floor and a wall surface sequentially. The detergent injection nozzles 13 are made to operate in the same way.