Hardware of each of controllers (11, 12, 13) for controlling a plurality of instruments to be controlled, which are provided in a reach stacker as a heavy duty industrial vehicle, for example, a vehicle body (3), a spreader (9), and a cabin (10), is rendered common. The configuration of driver software for performing basic control is also rendered common. Only the configuration of minimum required application software is constructed to be suitable for the instrument to be controlled. Because of these features, the software of the controllers (11, 12, 13) can be easily changed. Regardless of the instrument to be controlled, as a subject of control, the controllers can be easily used for any instruments to be controlled.