To define specifications for developing a high-speed plane grinding test device.

A test piece 5 is mounted to an outer periphery of a rotary table 3 via a test piece mounting fixture 4. The rotary table 3 is mounted to a laterally-facing table driving motor 1 via a shaft 2. A grinding stone 8 horizontally arranged corresponding to an upper end side position of a circular track of the test piece 5 with the rotation of the rotary table 3 is connected to a grinding stone driving motor 7 arranged downward on an upper portion of a rotation axis of the rotary table 3 to be movable in the direction of the rotation axis of the rotary table 3 via a grinding stone rotary shaft 9. A grinding process simulating a high-speed plane grinding process is performed on a ground surface 5a of the test piece 5 by a rotated grinding stone 8, while the test piece 5 is rotated at a higher speed than a speed of a ground material in a conventional table reciprocating-type plane grinding machine on a circular track by the rotation of the rotary table 3. By performing this process while changing various grinding conditions, a grinding condition for providing favorable grinding quality can be established.