An operation apparatus includes image capturing device capable of capturing images of a plurality of mark members provided in assembled members in a compartment; determining device capable of determining individually whether each of the mark members is or is not shielded on the basis of the image data taken and outputted by the image capturing device; and operation instructing device configured to output an operation command to on-board devices in accordance with a result of the determining by the determining device. Accordingly, it is easy for an operator to understand operational steps, thereby effectively preventing an erroneous operation due to the operator's misunderstanding. Furthermore, it is possible to simplify a determination logic of the operation instructing device, and also possible to easily provide a retrofitted option.