A data generation device generates at least a part of data used for a generation of an image displayed on a display unit. The display unit displays a workspace model modeled after an actual workspace, as a video. The workspace model includes a robot model modeled after an actual robot, and a peripheral object model modeled after a given peripheral object around the actual robot. The robot model is created so as to operate according to operation of an operator to a manipulator. The data generation device includes a state information acquiring module configured to acquire state information indicative of a state of the peripheral object, and an estimating module configured to estimate, based on the state information, a state of the peripheral object after a given period of time from the current time point, and generate a result of the estimation as peripheral-object model data used for a creation of the peripheral object model displayed on the display unit.