In an input data creation device, a reception unit is configured to acquire diagnostic information of a vehicle and traffic information output from an external device. A data generation unit is configured to extract vehicle status data including a plurality of data elements indicating a vehicle status from the diagnostic information to generate input data for operating a multimedia device for a vehicle. A command unit is configured to give an instruction such that the multimedia device operates based on the input data. The data generation unit is configured to set a timing at which traffic information is generated on a time axis of the input data, and change values of the data elements.