A drive device includes ceramic pumps which alternately pressurize and depressurize fluid within a fluid chamber on opposite sides of a movable body, to thereby move the movable body within the flow chamber. The flow chamber is connected via micro flow passages to an internal-pressure buffering chamber, which accommodates a compressible gas. When the pressure of the fluid is increased and decreased at high speed by the ceramic pumps, the micro flow passages exhibit a high passage resistance, so that the pressure within the channel does not escape to the internal-pressure buffering chamber, and the movable body moves freely. When the pressure of the fluid increases slowly due to the expansion of the fluid, the micro flow passages exhibit a low passage resistance, so that the fluid is led to the internal-pressure buffering chamber, and the pressure increase of the fluid is suppressed.