The three-dimensional form measurement by using images is used in the various fields, for example a computer vision, a robot vision, CAD, and so on. In the application, the three-dimensional measurement is often required to be fast. For the target which has the diffusion surface reflection characteristic, the active method is effective to a high-speed measurement. The active method includes the slit optical projection method, the method of the space encoding with a pattern projection, and the time series encoding pattern projection method, etc. However, there is a problem in an speed improvement as for each method. It is necessary for measurement to project several times at least. In this papaer, the concentric circle is used as a projection pattern,and we can mesure a object by projecting one time. It was confirmed in experiment that three dimensional measurement by using concentric circle is possible.