Abstract: A slurry supplying device by which a uniformly mixed slurry can be supplied to a blasting gun in a pressure-type wet blasting machine. The slurry supplying device comprises a substantially closed vessel which contains the slurry and has a conical section in at least one part of the vessel. A conical stop valve is freely movable up and down to close the bottom of the slurry settling section by sealingly fitting its conical edge on the conical section of the vessel. An air duct supplies low pressure air for agitating the slurry at a lower part of the closed vessel by raising the stop valve body. An air duct is provided for supplying highly pressurized air into the closed vessel for pressurizing the slurry. A slurry supply pipe is provided for supplying the pressurized slurry to the blasting gun. A pressure relief valve is mounted on the top plate of the vessel for maintaining a maximum air pressure in the upper portion of the vessel.