The present disclosure relates to a lawn mower robot, including an inner body; an outer cover configured to surround an outer side of the inner body; wheels rotatably mounted at both sides of the inner body, respectively; a rotating plate rotatably mounted on a bottom surface of the inner body, and disposed to be inclined downward with respect to a horizontal plane in a traveling direction of the inner body; a plurality of blades coupled to an edge portion of the rotating plate to be unfolded in a centrifugal direction and folded in the direction of the center of the circle, and spaced apart from each other in a circumferential direction of the rotating plate to cut grass while rotating around the rotating shaft of the rotating plate; and a blade protection cover formed to be spaced apart from the blades to prevent a fragment of an obstacle from being thrown out of the outer cover due to collision with the blades, wherein the blade has a cross-sectional shape of a parallelogram and is formed of a plate having a predetermined width in a longitudinal direction.