Abstract: In a micro-mechanical actuator having, disposed on a substrate, an actuator housing with a channel and a pressure chamber formed at one end of the channel, a piston with a guide rod projecting from one end and a piston rod projecting from the other end in the opposite directions is movably disposed in the channel and the rods are supported in slots formed in bearing blocks disposed at opposite ends of the piston for guiding the piston slideably in the channel, and a fluid admission and discharge passage extends through the substrate in the area of the pressure chamber whereby fluid can be admitted to, or removed from, the pressure chamber for actuating the piston.