Disclosed is a device for reducing a user-sensed weight of a wireless vacuum cleaner including a suctioning pipe and a suction motor disposed on a top of the suctioning pipe, the device comprising: a case disposed adjacent to the suction motor and having a space defined therein, and a rotatable assembly received in the space, wherein the rotatable assembly receives therein a motor and a battery, wherein the rotatable assembly is configured to rotate clockwise or counter-clockwise when the motor is activated.