<p>There is provided a work machine capable of surely judging whether an instrument such as a hydraulic breaker is in a work state. In a hydraulic shovel (1) having a breaker (7) operated by an vibration generation device (39) generating vibration upon reception of hydraulic oil from a hydraulic pump (16), a controller (45) is provided for judging that the breaker (7) is in a work state when a frequency analysis of a pump pressure waveform detected by a pressure sensor (48) results in that a range from f2 [Hz] to f9 [Hz] contains a frequency component having a power spectrum value not smaller than a power spectrum average value E2 multiplied by 2 and not smaller than E1 in an absolute value.</p>
