A robot cleaner includes a housing a sensor assembly disposed in the housing, wherein the sensor assembly comprises a light source configured to emit light toward an area in front of the housing; a camera unit comprising a lens; a reflector configured to reflect light incident on a front of the housing toward a front region of the lens; and a guide member hollow inside configured to guide light incident on a top of the housing toward a rear region of the lens. The robot cleaner estimates a current position of the robot cleaner more accurately by correcting the current position of the robot cleaner estimated by using odometry information based on images acquired by the camera unit.