The dental gypsum powder according to one aspect of the present invention comprises hemihydrate gypsum and a water reducing agent, wherein the mass ratio of the water reducing agent to the hemihydrate gypsum is 0.1% or more and 1% or less, and the particle content of the particle diameter of 10 μm or less is 15% by volume. The content of particles having a particle diameter of 20 μm or less is 40% by volume or more and 55% by volume or less, and the content of particles having a particle diameter of 30 μm or less is 55% by volume or more and 75% by volume or less.本發明一形態之牙科用石膏粉末中，包含半水石膏及減水劑，該減水劑相對於該半水石膏之質量比為0.1%以上1%以下，粒徑10μm以下的粒子含量為15體積%以上35體積%以下，粒徑20μm以下的粒子含量為40體積%以上55體積%以下，粒徑30μm以下的粒子含量為55體積%以上75體積%以下。
