To visibly measure a polishing proceeding state by supplying fluorescent tracer particulates having a high light accumulating effect on a polishing surface of a work and taking only a residual image light fluorescent particulate image by residual image light in the middle of shading in a CCD camera 22 by intermittently irradiating a laser beam.

A measurement data of polishing work pressure, etc., is provided by supplying the fluorescent tracer particulates high in the light accumulating effect to the polishing surface of the work W1 which is a transparent material from a fluorescent tracer particulate supplying device 4, irradiating the laser beam from a laser oscillator 11 in the middle of polishing work by a polishing pad 1 and taking the fluorescent tracer particulate image of the polishing surface in a picture image processing device 23 by the CCD camera 22. It is possible to provide the measurement data with no background light noise by the polishing pad 1, etc., by matching timing of picture image take-in by the CCD camera 22 with opening and closing of a high speed light OA shutter 12 and taking in the residual image light fluorescent particulate image by the residual image light in the middle of shading.