An action planning device, comprising: a failure detection unit configured to detect occurrence of a failure in outside-world recognition units and performs notification; an integration recognition unit configured to integrate outside-world recognition information output from the outside-world recognition units and output integration recognition information; and a trajectory generation/determination unit configured to send, to a drive unit, a control instruction to execute an action on the occurrence of the failure, on the basis of the integration recognition information output by the integration recognition unit; wherein the trajectory generation/determination unit is configured to send an instruction to take an action to cope with the failure, on the basis of the notification of the failure detection unit; and for the detection of the occurrence of the failure in the outside-world recognition units, the failure detection unit is configured to detect a failure occurring in a recognition device for acquiring outside world information or a failure occurring in a communication path between the recognition device and the integration recognition unit, and when it is determined that the failure occurs in a recognition of a specific area, the recognition device notifies the integration recognition unit that the recognition device has failed and transmits the specific area to the integration recognition unit as a failure occurrence range, which is a range in which recognition is disabled; and the trajectory generation/determination unit is configured to generate a trajectory to cope with the failure to enter a safe state, on the basis of past outside-world recognition information in the failure occurrence range notified by the failure detection unit; wherein the integration recognition unit is further configured to when the front side can be recognized and a straight path is continued, the integration recognition unit is configured to predict an action of a dynamic object in the failure occurrence range based on a learning result of the past action of a vehicle. a failure detection unit configured to detect occurrence of a failure in outside-world recognition units and performs notification; an integration recognition unit configured to integrate outside-world recognition information output from the outside-world recognition units and output integration recognition information; and a trajectory generation/determination unit configured to send, to a drive unit, a control instruction to execute an action on the occurrence of the failure, on the basis of the integration recognition information output by the integration recognition unit; wherein the trajectory generation/determination unit is configured to send an instruction to take an action to cope with the failure, on the basis of the notification of the failure detection unit; and for the detection of the occurrence of the failure in the outside-world recognition units, the failure detection unit is configured to detect a failure occurring in a recognition device for acquiring outside world information or a failure occurring in a communication path between the recognition device and the integration recognition unit, and when it is determined that the failure occurs in a recognition of a specific area, the recognition device notifies the integration recognition unit that the recognition device has failed and transmits the specific area to the integration recognition unit as a failure occurrence range, which is a range in which recognition is disabled; and the trajectory generation/determination unit is configured to generate a trajectory to cope with the failure to enter a safe state, on the basis of past outside-world recognition information in the failure occurrence range notified by the failure detection unit; wherein the integration recognition unit is further configured to when the front side can be recognized and a straight path is continued, the integration recognition unit is configured to predict an action of a dynamic object in the failure occurrence range based on a learning result of the past action of a vehicle.