To provide an image generation device for legibly displaying an output image to be generated on the basis of an input image to be picked up by image pickup means attached to a body to be operated which is capable of revolving.

An image generation device 100 for generating an output image on the basis of an input image to be picked up by a camera 2 attached to an upper revolving body 63 which is capable of revolving includes: revolving state detection means 120 for detecting the revolving state of the upper revolving body 63; CG image display control means 121 for superimpose-displaying a CG image 70 of the upper revolving body 63 on the output image; and output image update control means 122 for controlling the update state of the output image. When the start of revolution is detected by the revolving state detection means 120, the CG image display control means 121 makes the CG image 70 revolve on the output image.