Provided is a cleaner including a dust separation unit separating dust in the air, a suction flow path supplying outside air to the dust separation unit, a fan module moving the air in the suction flow path, and a dust sensor measuring concentration of dust in the suction flow path. The suction flow path includes a first suction flow path extending in a first direction and a second suction flow path connecting the first suction flow path to the dust separation unit and extending in a second direction that forms an obtuse angle with the first direction, and the dust sensor is disposed in the second suction flow path.