When a main switch (12) is turned ON, an electric operating machine (1) is put in the standby mode. With a trigger (13) being pulled in the standby mode, a power supply circuit (16) applies a voltage to a drive part (30). The power supply circuit (16) adjusts the voltage applied to the drive part (30) for a voltage corresponding to the pulling rate of the trigger (13). When the current running toward the drive part (30) exceeds the rated value of the drive part (30), the power supply circuit (16) automatically stops power supply to the drive part (30). On the other hand, when the output voltage of a battery (50) drops and the battery (50) is put in an overdischarge state, power supply to the drive part (30) is automatically stopped. When it is detected that the battery (50) undergoes an abnormal event, power supply to the drive part (30) is automatically stopped.
