PURPOSE: To hold a crystal plate of any shape and size by sucking and thereby to enable inspection of a cut face in an inspection apparatus of the cut face of the crystal plate.

CONSTITUTION: An inspection apparatus of a cut face of a crystal plate which inspects an angle of the cut face of the crystal plate 8 to a crystal lattice plane inside the crystal plate 8 and which has a crystal plate support stage 1 whereon the crystal plate 8 is set, an X-ray source 2 for applying an X ray to the crystal plate 8 set on the crystal plate support stage 1, and an X-ray counter 3 for detecting the X ray diffracted by the crystal plate 8. Moreover, this apparatus has three linear projections 6 provided on the crystal plate support stage 1 and extending radially from a point Q as the center and air holes 7 for sucking the crystal plate which are opened in the surface of the crystal plate support stage 1.