A fan motor unit and a vacuum cleaner having the same are provided. The fan motor unit includes a motor assembly comprising an impeller and a motor, a first upper case configured to surround the motor assembly, the first upper case comprising an inlet tube in communication with an entry of the impeller, configured to a first lower case configured to surround a lower portion of the motor assembly, a damper and a pressure switch, each in communication with the inlet tube and, a warning member connected to the pressure switch, wherein when the pressure of the interior pressure of the motor assembly is below a predetermined value, external air is flowed through the damper and a warning is generated by the warning member and the pressure switch.