Some embodiments of the present invention provide a cleaning device, a washing machine, and a detergent dispensing method. The cleaning device includes a first accommodation portion, a first detection portion and a control portion. The first accommodation portion has a water inlet portion and a water outlet portion. At least part of the first detection portion is disposed in the first accommodation portion. The first detection portion is configured to detect a flow speed of a liquid flowing into the first accommodation portion 10 from the water inlet portion. The control portion is electrically connected to the first detection portion. The control portion is configured to control a water inlet duration of the water inlet portion 11. At least part of the first detection portion is disposed in the first accommodation portion to detect a flow speed of a liquid flowing into the first accommodation portion, and then the control portion controls a water inlet duration of the water inlet portion of the first accommodation portion to control a total water inlet amount. This arrangement allows the washing machine to accurately control the water inlet amount, so that the water inlet amount of the washing machine and the detergent are fully integrated, thereby improving the washing effect of the washing machine.