To provide an abrasive fluid supplying device for mechanochemical polishing, capable of supplying the abrasive fluid whose properties are always constant to polishing device without change of concentration caused by fluctuation of the mixing ratio of abrasive undiluted fluid to solvent and without change of concentration caused by precipitation of abrasive fine grains.

Only one set of a undiluted liquid measuring tank 4 for measuring abrasive undiluted fluid from a undiluted liquid tank 1 and a solvent measuring tank 6 for measuring solvent such as water is provided, the fluid are mixed by measuring them under the always same condition, so as to held the mixing ratio of the abrasive undiluted fluid to the solvent constant. The abrasive undiluted fluid or abrasive fluid in the undiluted liquid tank 1, the undiluted liquid measuring tank 4, a mixing tank 9 and a supplying tank 11 are agitated by being always circulated through supplying pipes 16, 28, 45, 50 attached to respective tanks and circulating pipes 17, 29, 46, 51 by pumps 18, 31, 47, 52, and abrasive fine grains are prevented from being precipitated.