To suppress the occurrence of the strain of a platen due to thrust of an actuator to exert a vertical force on the platen to suppress an arrangement space for a detecting sensor to detect the vibration state of an object to be vibration-insulated and support an object to be vibration-insulated.

An arrangement space for a detecting sensor is suppressed in such a way that acceleration in three translation directions (an X-direction, an Y-direction, and a X-direction) of an exposing device body 30 and three angular speeds around an X-axis, an Y-axis, and a Z-axis are measured by three acceleration sensors arranged in the vicinity of three corner parts on the upper surface of a platen 6. An actuator to provide thrust in a Z-direction and a mount part, consisting of an air damper, of which a vibration insulation mount 3A consist, are arranged substantially in parallel between the platen 6 and a base frame 2. The occurrence of the strain of the platen 6 is suppressed in such a way that the working line of the mount part coincides with the thrust central line of the actuator.