Over the past decade, microbe and DNA research in biotechnology has progressed rapidly. In particular, it is important to pick up a speci c microbe to study and analyze it. In the past, some researchers use mechanical micromanipulators with the PZT stage, etc. However, they could not obtain high purity separation of objects in the micrometer size range nor manipulate them in the enclosure environment. Thus we must change the approach method from the conventional mechanical manipulation method to a non-contact manipulation method, e.g. laser manipulation, dielectrophoretic manipulation, etc. We have developed a random separation system for a micro-object in a microchip by laser manipulation and dielectrophoresis [1]. Here we employed laser manipulation by a laser trap. A laser trap is known be able to trap a small object by optical momentum change. The advantage of laser manipulation is that we can handle the micro-object in a non-contact way. However, it is dif cult to control the trapped object because it is easily disturbed. Thus, we must observe whether the object is trapped or not. If the operator can feel the laser trap force, the operability of the laser manipulation will be improved. Thus, we developed a bilateral control system for laser manipulation [1–3]. Figure 1 shows an overview of our laser manipulation system. This system employs a 200 mW semiconductor laser. A Quadrant Photodetector (QD) is used as a position detector for the trapped object. The PZT xy-stage controls the laser focus position. It can detect the distance (x ) between the laser focus (Xs) and the center of the object (z). x is used to estimate the optical spring force F D K.x/x