A mobile body delivers a package to a designated destination by autonomous traveling. When the mobile body arrives at the destination, door status information including opening/closing status of an entrance door of the destination is acquired, and it is determined whether the entrance door of the destination has been opened based on the acquired door status information. When the entrance door has been opened, a delivery of the package to the destination is authenticated, and a locking device for regulating the delivery of the package from the mobile body is unlocked.