To provide a CMP conditioner having excellent corrosion resistance in the portions around abrasive grains.

A base body of an abrasive stone has an abrasive grain layer on one side surface thereof, the layer in which, abrasive grains are fixed in a metallic bond phase. A first protective layer composed of oxide is formed on the surface of the metallic bond phase in the abrasive grain layer by the sol-gel method. Next, a second protective layer composed of a thick oxide film is formed on the surface of the first protective layer by jetting aero-sol having fine powder of a brittle material distributed in gas and making the aero-sol collide with the surface of the first protective layer.