To provide an adsorbent adsorbing floating components such as fine resin such as a coating material, and simultaneously performing separation treatment by a simple means, e.g., of floating up the one adsorbed therewith on the upper layer in water and skimming the same.

The adsorbent for underwater floating coating particles or the like is composed of: (A) glass foam obtained by collecting and mixing glassy material powder of 100 pts.mass, Kanuma soil powder and Akadama soil powder of 50 to 80 pts.wt and foaming material powder of 10 to 20 pts.wt., firing and foaming the mixture in a furnace of 800 to 1,100°C so as to be made into a powdery body or a granular body; (B) a flocculant of linking the glass foam; (C) a cotton-shaped fibrous stock obtained in such a manner that fibers are partially interlaced to a degree that the glass foam and the particles of the flocculant can be involved and (D) a surfactant making the system into the hydrophobic one.