A control apparatus controls a detachable electric instrument. The control apparatus includes a drive signal output unit configured to output a drive signal to the electric instrument a relay provided in a sending route of the drive signal a switching unit configured to output a switching signal that switches the relay between ON and OFF an inspection signal output unit configured to output an inspection signal that inspects the relay to the sending route in a state in which the electric instrument is not connected and a blocking determining unit configured to determine whether the inspection signal is blocked by the relay in a state in which the relay is turned OFF by the switching signal.
