A hydraulic cylinder system 1 is provided with a plurality of cylinders 3a and 3b, valves 4a and 4b provided at each of the cylinders 3a and 3b for adjusting amounts of operating fluid into and out of the cylinders 3a and 3b, driving systems 5a and 5b having motors 6a and 6b provided at each of the valves 4a and 4b for driving the valves 4a and 4b, and a connecting member 8 for connecting the motors 6a and 6b of the driving systems 5a and 5b in a manner capable of interlocking with each other.