An image generation device for an excavator, said excavator comprising a lower-part running body, a turning mechanism, and an upper-part turning body, the image generation device being adapted to generate an output image based on a plurality of input images image-taken by a plurality of image-taking parts (2, 2B, 2R) mounted to the upper-part turning body, the image generation device comprising: a coordinates correspondence part configured to cause coordinates on a cylindrical space model, which is arranged to surround said upper-art turning body and having a center axis (Z, PV, J1, J2) and a side surface, to correspond to coordinates on a plurality of input image planes on which the plurality of input images are positioned, respectively; and an output image generation part configured to generate said output image by causing values of the coordinates on said plurality of input image planes to correspond to values of the coordinates on an output image plane on which said output image is positioned through coordinates on said cylindrical space model, wherein a minimum value of a distance between the center axis (Z, PV, J1, J2) and the side surface of said cylindrical space model is determined to be a distance between the center axis (Z, PV, J1, J2) and an intersection point of boundary lines (BL1, BL2) on the road surface at positions away from the excavator by a predetermined distance, the predetermined distance being determined by installation positions of the image-taking parts (2, 2B, 2R), respectively separating a range, which is not hidden behind a vehicle body of the upper-part turning body such that an image thereof can be taken, and a range, which is hidden behind the vehicle body such that an image thereof cannot be taken, when two image-taking parts (2B, 2R) of the plurality of image-taking parts (2, 2B, 2R) that are attached to the upper-part turning body in an obliquely downward direction so that they do not protrude out of the upper-part turning body of the excavator and that have overlapping image-taking ranges take images from their respective installation positions. a coordinates correspondence part configured to cause coordinates on a cylindrical space model, which is arranged to surround said upper-art turning body and having a center axis (Z, PV, J1, J2) and a side surface, to correspond to coordinates on a plurality of input image planes on which the plurality of input images are positioned, respectively; and an output image generation part configured to generate said output image by causing values of the coordinates on said plurality of input image planes to correspond to values of the coordinates on an output image plane on which said output image is positioned through coordinates on said cylindrical space model, wherein a minimum value of a distance between the center axis (Z, PV, J1, J2) and the side surface of said cylindrical space model is determined to be a distance between the center axis (Z, PV, J1, J2) and an intersection point of boundary lines (BL1, BL2) on the road surface at positions away from the excavator by a predetermined distance, the predetermined distance being determined by installation positions of the image-taking parts (2, 2B, 2R), respectively separating a range, which is not hidden behind a vehicle body of the upper-part turning body such that an image thereof can be taken, and a range, which is hidden behind the vehicle body such that an image thereof cannot be taken, when two image-taking parts (2B, 2R) of the plurality of image-taking parts (2, 2B, 2R) that are attached to the upper-part turning body in an obliquely downward direction so that they do not protrude out of the upper-part turning body of the excavator and that have overlapping image-taking ranges take images from their respective installation positions.