A gas distribution plate that is installed in a chamber providing a reaction space and supplies a reaction gas onto a substrate placed on a substrate placing plate, wherein the gas distribution plate includes: first and second surfaces opposing to each other, wherein the second surface faces the substrate placing plate and has a recess shape; and a plurality of injection holes each including: an inflow portion that extends from the first surface toward the second surface; a diffusing portion that extends from the second surface toward the first surface; and an orifice portion between the inflow portion and the diffusing portion, wherein the plurality of inflow portions of the plurality of injection holes decrease in gas path from edge to middle of the gas distribution plate, and wherein the plurality of diffusing portions of the plurality of injection holes have substantially the same gas path.