Abstract: A device casing including a bottom plate, a first side plate, a second side plate opposite to the first side plate, a third side plate and two pivoting elements is provided. The bottom plate is connected to the first side plate and the second side plate respectively to form a U-shaped frame having an opening end opposite to the bottom plate. The third side plate is pivotally connected to the first side plate and the second side plate respectively. The two pivoting elements are configured to fix but rotatably connect the third side plate to the first side plate and the second side plate respectively. The two pivoting elements are adjacent to the opening end. The third side plate whose axis of rotation is an imaginary line connecting the two pivoting elements is optionally movable between a closed position and an opened position.