An invented battery-operating multifunctional apparatus in use for such as office automation provides an adequate threshold level thereby to detect a low energy state of the battery by discriminating whether species of a head loaded on a carriage unit 7 is an ink head 401 for printing the characters or a scanner head 402 for reading the image pictures. To attain the purpose, the threshold value of the low battery state is lowered for the scanning operation compared with for the printing operation.