When recording image data inputted from a plurality of data ports and a clock port, for a data port at which the data value has not changed over a predetermined time period, the data value at that data port and a data item which indicates that this data value has continued unchanged are recorded. Consequently, PC can be connected or expanded conveniently and, with the help of one or specialized flat cables, the assembly process of connecting interface is easy. Optical and computer realization of the employed hologram are accomplished along with sensor configurations in simple and more complex uses. A first actuating member operates the damping force adjustment valve and a second actuating member operates the damping lockout mechanism such that the damping force adjustment valve remains in a set position when the second actuating member is being operated.