This device features a filter cleaning system that automatically removes dust adhering to the filter (even during continuous operation) and thus reduces filter clogging to prevent a decline in suction power. A second filter cleaning is automatically performed when the device is turned on and off. When the power is turned on, a pre-filter collapses, compressing the damper. When the device is turned off, it expands back to its original size, automatically shaking off the dust from the pre-filter with its expansion force. The cordless vacuum cleaner has a mechanism that prevents water from entering the motor when the liquid level reaches a certain amount. When the tank is full, the device automatically stops. Turn off the device after it has stopped and empty the tank. Simple emptying is possible via a water drain cap.