To provide a thin plate material holder that holds the thin plate material without causing damages.

A thin plate material holder to hold thin plate materials is provided with a holding part 1 and a supporting part 2. The holding part 1 is provided with a first holding member 3 with a first holding curved surface and second holding member 5 with a second holding curved surface. The first holding curved surface 4 and the second holding curved surface 6 are arranged to face each other. The supporting part 2 is provided with a first supporting member 7 to support the first holding member 3, a second supporting member 8 to support the second holding member 5, and a movable supporting member 9. The movable supporting member 9 supports the first supporting member 7 and the second supporting member 8 so that they can be moved to a holding position and a releasing position.