1. A video creation device comprising: a successive creator for successively and alternately creating, through imaging, a frame of a first type and a frame of a second type, wherein a frame of the second type have a shorter exposure than the frame of the first type; a difference determiner for determining whether or not the difference between frames of a determination pair exceeds a prescribed threshold, wherein the determination pair contains two frames of the first type next to each other in imaging timing, or the frame of the first type and the frame of the second type next to each other in imaging timing; a frame creator for creating, when the difference determiner determines the difference exceeds the threshold, a frame of a third type between frames of a data pair in imaging timing based on the frames of the data pair, wherein the data pair contains two frames of the first type next to each other in imaging time and at least one frame is contained in the determination pair; a synthesizer for creating high-dynamic-range frame by successively synthesizing frames of synthesized pair, wherein synthesized pair contains the frame of the second type and the frame of the first type next to the frame of the second type in imaging timing, or the frame of the second type and the frame of the third type next to the frame of the second type in imaging timing; and, a video creator for creating video comprised of the frame synthesized by the synthesizer.