An electric working machine comprising: a motor; an acceleration sensor configured to detect a vibration of the electric working machine and output a detection signal corresponding to the vibration; a load-determiner configured to determine whether the electric working machine is placed in no-load-imposed state or in load-imposed state based on the detection signal from the acceleration sensor, the load-determiner being configured to drive the motor in a low-speed rotation mode in response to a determination by the load-determiner that the electric working machine is placed in the no-load-imposed state, and the load-determiner being further configured to drive the motor in a high-speed rotation mode in response to a determination by the load-determiner that the electric working machine is placed in the load-imposed state; a filter part having a cutoff frequency, the filter part being configured to remove, based on the cutoff frequency, an unwanted signal component from the detection signal outputted from the acceleration sensor, the filter part being further configured to input, to the load-determiner, the detection signal with the unwanted signal component removed, and the unwanted signal component corresponding to a vibration of the electric working machine unnecessary for a determination by the load-determiner; and a filter-property setting part configured to change the cutoff frequency of the filter part such that the cutoff frequency in the high-speed rotation mode is higher than the cutoff frequency in the low-speed rotation mode, wherein the filter-property setting part is configured to change the cutoff frequency of the filter part in response to an elapse of a given length of time since a rotation mode of the motor is changed by the load-determiner. a motor; an acceleration sensor configured to detect a vibration of the electric working machine and output a detection signal corresponding to the vibration; a load-determiner configured to determine whether the electric working machine is placed in no-load-imposed state or in load-imposed state based on the detection signal from the acceleration sensor, the load-determiner being configured to drive the motor in a low-speed rotation mode in response to a determination by the load-determiner that the electric working machine is placed in the no-load-imposed state, and the load-determiner being further configured to drive the motor in a high-speed rotation mode in response to a determination by the load-determiner that the electric working machine is placed in the load-imposed state; a filter part having a cutoff frequency, the filter part being configured to remove, based on the cutoff frequency, an unwanted signal component from the detection signal outputted from the acceleration sensor, the filter part being further configured to input, to the load-determiner, the detection signal with the unwanted signal component removed, and the unwanted signal component corresponding to a vibration of the electric working machine unnecessary for a determination by the load-determiner; and a filter-property setting part configured to change the cutoff frequency of the filter part such that the cutoff frequency in the high-speed rotation mode is higher than the cutoff frequency in the low-speed rotation mode, wherein the filter-property setting part is configured to change the cutoff frequency of the filter part in response to an elapse of a given length of time since a rotation mode of the motor is changed by the load-determiner.