A travel route generation device includes circuitry configured to define a shape of a work field by calculating a first line connecting a starting point and one of intermediate points, and a second line connecting another of the intermediate points and an end point. The circuitry is configured to calculate a shape of an entrance passage in the work field though which a work vehicle is to enter a target work region in which the work vehicle is to work in the work field. The entrance passage has a shape of a substantially quadrangle including a first side extending along the first line from the starting point and a second side extending along the second line from the end point. The circuitry is configured to generate a travel route along which the work vehicle is to travel in the target work region.
