There is disclosed is a liquid immersion optical tool, which comprises a light source, an optical lens system, a stage which moves an object base on which an object is to be placed, a head comprising a liquid immersion medium fluid supply device and a liquid immersion medium fluid discharge device to provide a layer of liquid immersion medium fluid between the optical lens system and the object, a fence which limits a region of the layer of liquid immersion medium fluid, and a cleaning device which cleans a portion having been contacted with the liquid immersion medium fluid by means of a cleaning solution.