To provide a lightweight and highly rigid stage device that can move in X and Y directions and a Z direction, and a charged particle beam device including the stage device. A stage device includes a chuck that is loaded with a sample, an XY stage that moves in X and Y directions, and a Z stage that moves in a Z direction. The Z stage includes: an inclined part that is fixed to the XY stage and includes an inclined surface inclined with respect to an XY plane; a movement part that moves on the inclined surface; and a table that is fixed to the movement part and is provided with the a plane parallel to the XY plane.