Provided is a cleaner including a dust collecting device for separating dust from air, wherein the dust collecting device includes a dust collecting case having a dust discharging port opened to discharge the collected dust; a discharge cover coupled to one side of the dust collecting case to open and close the dust discharge port; and a sealing member provided to extend from an inner surface of the dust collecting case to a coupling surface of the dust collecting case while being in contact with the dust collecting case and thus to be sealed when the dust discharging port is closed.