A network device is provided with a storage and adapted to be connected to a network. A document acquirer is operable to acquire a structured document in which a rule of processing executed by the network device is described by at least one first element defining at least one condition and at least one second element defining at least one content of the processing. A document analyzer is operable to analyze the structured document to obtain an analysis result and to store the analysis result in the storage. An operation controller is operable to control an operation of the network device in accordance with the analysis result stored in the storage.