PURPOSE: To downsize a power conversion device, prevent errorneous operation, and simplify wiring and piping by providing any of functions of computing, memorizing, program execution, signal input, transferring signals between actuators, and enabling speedy and certain energizing and controlling.

CONSTITUTION: A conductor 16 which is connected to a power source 28 and an optical fiber 32 are parallelly connected to actuators 20a to 20f, which optical fiber functions for receiving address and data signals from a computer 30 serially and parallelly. Control parts 36 which are provided on the actuators 20a to 20f together with cylinders 34 are each composed of a valve mechanism 52 for controlling the actuators through a solenoid valve, an input/output circuit 54, a detecting means 56, a driving means 58 and a computing means 60. The computing means 60 which is composed of a memory, a CPU, and a communication interface selectively takes in a data signal corresponding to characteristic address thereof among the ones from the optical fiber 32. Wiring and piping are thus omitted, speedy and certain operation is secured, and errorneous operation is prevented.