The present invention provides a network image synthesizing display system. Camera images taken by a plurality of cameras (101, 102 and 103) are multicast and sent via the network by a plurality of sending devices (110, 111 and 112). A synthetic parameter calculating device (105) uses the camera images and calculates such synthetic parameters in a manner to correspond to image processing devices (106, 107, 108 and 109) as are necessary for synthesizing the display images to be displayed in display devices (113, 114, 115 and 116), and sends those synthetic parameters to the image processing devices (106, 107, 108 and 109). On the basis of those synthetic parameters, the image processing devices (106, 107, 108 and 109) synthesize the camera images into display images. As a result, the display images are distributively synthesized by the individual image processing devices.