1. A vehicle surroundings awareness support device comprising: an image reception unit for receiving captured images comprising a plurality of frames taken sequentially by an onboard camera for imaging the surroundings of a vehicle; an optical flow computation unit for computing an optical flow on the basis of feature points contained in the plurality of frames imaged at different times; a moving object detection unit for detecting a moving object in the surroundings of the vehicle on the basis of the optical flow; and a superimposing unit for superimposing a display for showing movement trajectories for the moving objects onto the captured images, on the basis of the optical flow.