A controller (2) which transmits code signals in accordance with operation contents of a user, a drive unit (1) driven and controlled based on the code signals, and an extension unit (10) detachably mounted on the controller (2) are provided. A code signal obtaining device (31, 51, and 52) for obtaining the code signals output from the controller (2) and a process performing device (30 and 61) for deciding a state of the drive unit (1) based on the obtained code signals to perform a predetermined process based on the decision result are provided in the extension unit (10).