Abstract: A device determination system includes an assistance device configured to assist a work for a workpiece stacked in a stacking area and having portability so as to be freely arranged, an image capturing device capable of capturing an image of the stacking area, and a control device configured to determine an arrangement position and an arrangement orientation of the assistance device in the stacking area based on the captured image captured by the image capturing device, in which the assistance device includes an indicator by which a position and an orientation of the assistance device reflected in the captured image can be identified, and the control device detects the indicator included in the captured image so as to determine the arrangement position and the arrangement orientation.