In this study we discuss the applicability of a high-damping rubber damper, which is composed of micro-networks and viscous material, as the damping device in microvibration-isolation devices or tables. For those purposes, damping force characteristcs of the high-damping rubber damper were measured using a new measuring device. We could estimate damping force characteristics to a shear displacement amplitude of 2.5×10-6m, and this high-damping rubber damper was found to have energy-absorption capacity in the regions of very small shear displacement amplitude. Also, the damping force characteristics of a viscous shear damper using silicone oil, which is the most popular damper for vibration-isolation devices, were measured. On comparing the damping force characteristics, our high damping rubber damper was found to have a larger energy absorption ability than the viscous shear damper. Furthermore, the rubber dampers were installed to the vibration isolation table which can mainly isolate microvibrations in horizontal direction. Through microvibrationisolation tests it was confirmed that this high damping rubber could be applied to microvibrationisolation devices.