A data recording/reproducing apparatus includes a first power source unit which generates necessary electric power signals from a commercial power source, and a second power source unit which generates a necessary electric power signal from the commercial power source. When a user issues an instruction to interrupt the operation of the power source of the apparatus, the generation of the electric power signal of the first power source unit is stopped, and the electric power is supplied to at least two of a control unit for controlling switching of operation states of the apparatus, a reception unit for receiving a manipulation instruction, and a display unit for displaying thereon data relating to the operation state from the second power source unit.