To produce and supply a mixture with a simple constitution by constituting so that powder in a powder vessel is measured by a fixed delivery valve to supply to a mixing vessel, a prescribed quantity of fluid is supplied to the mixing vessel by a fluid supply means and the mixture mixed therein is supplied.

At the time of being applied for a mixing and supplying device for supplying a detergent mixed with water to a large washing machine for the business, a fixed delivery valve 9 for powder is worked by a solenoid valve unit 57 to fall down the prescribed quantity of the detergent in a detergent vessel 3. And then the fixed delivery valve 9 for powder is worked by a solenoid valve unit 57 to fall down the prescribed quantity of the detergent to the mixing vessel 27, the prescribed quantity of water is supplied to the mixing vessel 22 with a water supply solenoid valve 37 worked. Then, the prescribed quantity of the detergent and the prescribed quantity of water are supplied to the mixing vessel 27 and are mixed with each other in the mixing vessel 27. The detergent and water mixed in the mixing vessel 27 are next supplied to the large washing machine through a water supply pipe line by a pump 41.