To enable conveniently positioning a comparatively small-sized and lightweight work with a small setting space and at low cost, by placing a work to be positioned on the surface of liquid held in a definite shape on a base material, and by moving the work by use of surface tension of the liquid to position.

Liquid 1 for generating surface tension is held on a base 3 by use of a liquid holding frame 2. If a plate-like work 4 is moved down to the surface of the liquid 1, the work 4 has a movement of being attracted in certain direction (normally toward the vicinity of the center) instantly. As a result, a comparatively small-size and lightweight work 4 can be conveniently positioned in a small space and at low cost.