Within an injector housing, a nozzle needle comprising a nozzle needle shaft is accommodated in a first guide boring in a longitudinally displaceable manner. Calculation means changes a pulse width and a pulse-quiescent width in accordance with a DC voltage detection value, using a pulse width determination section, such that a desired accuracy of magnetic-pole position detection can be obtained regardless of variation in DC voltage of a DC voltage source. The control unit estimates multiple possible control patterns and calculates evaluation values related to the cooling efficiency for respective cases, in which a compressor is operated in accordance with each of the control patterns. An environment adaptive noise model comparing unit obtains a likelihood that respective recognizing-unit standard patterns coincide with a time series of the amount of characteristics representing the characteristics of the input speed.