In a brush cutter (100), when it is determined based on acceleration information including frequency components, supplied from an acceleration sensor (24) included in the brush cutter (100) that the acceleration shows a peak in a range of frequencies lower than 100 Hz, the flow moves to step S5 to amplify the acceleration peak. In next step S6, the acceleration peak is compared with a threshold. When the result of comparison shows that the acceleration peak is higher than the threshold, the flow moves to step S7 to produce a safety signal. The safety signal is output from the controller (26) to a high voltage generation circuit (30) to stop generation of a high voltage in the high voltage generating circuit (30). In this manner, the acceleration sensor (24) is used to detect any unexpected, sudden danger, while diminishing influence of the acceleration caused by vibration inherent to the own nature of the work apparatus, its intended regular operation and its posture change in regular operation.