Vehicle systems that implement action planning for a vehicle have had difficulty in maintaining safety in the event of a failure in a recognition device since these systems generate trajectories and control the vehicle on the basis of outside-world information recognized by recognition devices. The present invention was conceived in light of the aforementioned situation and addresses the problem of maintaining safety even in the event of a failure in a recognition device of a vehicle system. This problem can be solved by an action planning device having a failure detection unit for detecting a failure in an outside-world recognition unit and a trajectory generation/determination unit for executing an action on the occurrence of a failure on the basis of outside-world information outputted by the outside-world recognition unit, wherein the trajectory generation/determination unit takes an action for coping with the failure on the basis of failure information from the failure detection unit.