To provide an information generation device and the like that, when generating transmission data of inter-mobile body communication having a limited data amount, generate information that can be effectively used by a mobile body on a reception side. An information generation device 1 mountable on a mobile body (5), the information generation device 1 estimating a control attribute concerning driving control for another mobile body existing in a communicable range from a position of the mobile body (5), the control attribute being a control attribute of mobile bodies relatively large in number, (S4) and generating information for transmission transmitted to the other mobile body, the information for transmission including mobile body information of an item prioritized according to the estimated control attribute among a plurality of items of mobile body information including information concerning the driving control for the mobile body (5) (S7).