IN-VEHICLE PROCESSING DEVICE

An in-vehicle processing device includes an offset route generation part configured to generate an offset route by offsetting to an oncoming lane an outbound route in a street on which the host vehicle has previously traveled, a candidate point generation part configured to generate a plurality of candidate points that are candidates for a return route based on the offset route generated by the offset route generation part, a candidate route generation part configured to generate a plurality of candidate routes by connecting the candidate points generated by the candidate point generation part, and a route selection part configured to select the return route based on the plurality of candidate routes generated by the candidate route generation part.