A robot cleaner includes: a suction module configured to suck dust-included air; a cyclone module configured to separate dust from the dust-included air sucked through the suction module, and having a dust discharge opening; a first air flow guide and a second air flow guide spaced apart from each other, and connecting the suction unit to the cyclone unit; a dust box detachably coupled to the dust discharge opening of the cyclone module, and provided between the first and second air flow guides; a drive module provided between the first and second air flow guides; and a dust compressor provided in the dust box, and mechanically coupled to the drive module when the dust box is mounted to the cyclone module, and formed to be rotatable bi-directionally based on a driving force from the drive module such that dust collected in the dust box is pressed to have a deceased volume.