A document presentation device 10 includes a video signal controller 50 adapted to output a video signal of a video image for display on a display unit 40; and a remote controller RC. The video signal controller 50 includes a video signal processing unit 60 for creating a live video image within the field captured by an image sensor 31a; a masking setting unit for setting the brightness differential of the masking region; and a masking image display control unit that upon receiving an instruction from a masking instruction unit of the remote controller RC, sets a portion of the live video image to a masking region based on settings that are set in advance through the masking settings portion, and displays the live video image on the display unit 40; and that upon receiving an instruction from a position instruction unit of the remote controller RC changes the position of the masking region.