A locator apparatus configured to be applied to a vehicle includes first processing circuitry and first communication circuitry. The first processing circuitry is configured to generate traveling road data and conversion data, based on a map database in which map data is stored in advance. The traveling road data is represented as a vehicle coordinate system relative to the vehicle and includes data indicating a location of a traveling road in a partial region set relative to the vehicle in a direction in which the vehicle is likely to travel. The conversion data is usable for coordinate conversion from the vehicle coordinate system into an absolute coordinate system. The first communication circuitry is configured to transmit time-series data of the traveling road data and time-series data of the conversion data.