The invention provides a dental gypsum-bonded investment material powder which can inhibit air bubbles from being generated in a mixed material, only by being mixed with water without using any special device or tool, and is easily mixed with the water. A specific siloxane is blended at a specific amount in relation to the dental gypsum-bonded investment material powder which includes an anionic surfactant and is excellent in a mold releasing action. In other words, the dental gypsum-bonded investment material powder is structured such as to have 0.001 to 0.2 weight % anionic surfactant, and 0.00001 to 0.0005 weight % cyclic siloxane having 3 to 10 SiO(CH 3 ) 2 units.