To shorten polishing time by improving polishing efficiency by excellently supplying an abrasive to the contact portion between the inside end surface 1a of a glass substrate 1 and brush bristles 4.

Glass substrates 1 are dividedly stored in a plurality of cartridges 60, and the cartridges 60 are stored in a substrate storing case 10 in series. The cartridge 60 is a coaxial different diameter cylindrical body, and is composed of a large diameter substrate storing cylindrical portion 61 for storing laminated glass substrates 1 and a small diameter connecting cylindrical portion 62 forming a polishing fluid passage. Inlet openings 62b for polishing fluid are provided on the side surface of the connecting cylindrical portion 62. When the cartridges 60 are stored in the substrate storing case 10 in series, the substrate storing cylindrical portions 61 of respective cartridges 60 are connected with the connecting cylindrical portions 62, and also polishing fluid passages are formed between respective substrate storing cylindrical portions 61. Therefore, polishing fluid can be uniformly supplied in the round holes of the glass substrates 1 in the respective cartridges 60.