The textile material is subjected to many kinds of mechanical treatments during the production process. It has been wanted to construct a testing machine which not only performs a static test but also produces arbitrary deformation or load on the material and simulates the actual production process. We have constructed a tester having these abilities using a hydraulic servo system. The relsuts to be reported in this paper are as follows: 1. The deformation input tester is able to simulate the actual processes sufficiently.2. In the load input tester, a test piece is set in series with the spring by means of an operating cylinder. As the spring converts deformation to load, an arbitrary load is applied to the test piece by this mechanism.3. The practical method to avoid the influence of mechanical properties of testing material on the characteristics of the tester has been developed theoretically and experimentally.4. If the phase lead compensation circuit is placed before the hydraulic servo system and the following conditions are satisfied, the influence of material can be avoided. Tf·T<<K·Tf. where Kf: compliance of test piece, Kf: time constant of test piece K: bulk gain of servo system, T: time constant of servo system.5. As an example of the practical treatment in which the material is subjec t ed to deformation or load, we studied the fluctuations of warp tension with shedding motion of the loom, and found that this tester has an ability to generate the high frequency component of the wave and that an experiment can be performd to simulate the high speed operation.