The International Thermonuclear Experimental Reactor Project (ITER Project) aims to make the long-awaited transition from experimental studies of plasma physics to full-scale electricity-producing fusion power stations [1]. It fuses the hydrogen isotopes deuterium and tritium into helium and a free neutron. In order to start fusion reaction the temperature has to be about 150 million Kelvin. Because there is no material, which could withstand such high temperatures, the plasma is guided contactless by magnetic fields within the vacuum chamber. However, these fields are not fully closed, resulting in the escape of high energy particles. These particles are constantly hitting the inner wall of the reactor, which leads wear effects, affecting the overall performance of the Tokamak. Thus, there is a need for the continually measuring of the erosion at the wall, after the Tokamak was operating. An erosion monitor able to measure the changes in the surface shape with a depth resolution of 10 μm is planned. The erosion (change of shape) measurement will be done not on the whole internal surface of the Tokamak but only on two surfaces having each a size of 10x30 cm². Due to the high temperature and the radiations it will not be possible to have the measuring system inside the Tokamak, for this reason the measurements will be performed remotely where the opto-electronic instruments (detector, laser, controlling electronic) will be located at a distance of about 20 m from the surface to be measured. We will show that long distance shape measurements in challenging environmental conditions can be done by two (or multi) wavelengths digital holography [2, 3] and thus this technique could be used for the erosion monitoring inside the Tokamak