To provide a slide-machining technique for slide-machining precisely a work to be machined, without generating a dispersion of machining quality.

Outside air is introduced into a tub 4 by connecting an ejector pump mechanism 12 to an exhaust port 11 provided in side face of the tub 4, and by sucking and exhausting forcibly mist and heat filled in the atmosphere 4a of a machining space in an inside of the tub 4 during polishing machining, and the polishing machining of high precision is carried out thereby without generating the dispersion of machining quality in the lens 5, by keeping constant a machining condition such as a temperature and humidity in the atmosphere 4a of the machining space, in a polishing machining device M1 for sliding a polishing functional face 1a of a polishing tool 1 driven by a motor 3 via a tool base body 2, and an optical functional face 5a of a lens 5 supported by a lens receiving tool 6 while supplying a polishing liquid 8 from a nozzle 7, in the tub 4 provided with a cover 9.