A robot cleaner capable of extending the service life of a filter by including a cyclone unit is provided. The robot cleaner includes a main body including wheels configured to rotate about a rotation axis, a brush device provided in the main body to draw in air containing dust, a first chamber, through which the air drawn in through the brush device is introduced, configured to change a traveling direction of the introduced air, and a second chamber connected to the first chamber and including a dust separator separating dust contained in air, and arranged side by side with the first chamber in a direction in which the rotation axis extends.