Information acquisition control unit, information acquisition control system, Information acquisition control method, Information acquisition control program, recording medium with the program recorded therein, and navigation system

When information is acquired, also information concerning the current date and time is required. Time information concerning the term of validity or the like included in the information previously acquired is read by the communication possibility determining section ( 485 ). If the current data is not over the term of validity, it is determined that the communicating operation can not be executed. When the term of validity has expired, it is determined that the communicating operation can be executed. When it is determined that the communicating operation can be executed, the set processing section ( 483 ) controls the terminal communication section ( 410 ) to execute the processing for acquiring information from the main server device ( 300 ) or the like. With the configuration, increase of processing load and communication cost due to execution of unnecessary communicating operations can be prevented, and efficient information acquisition can be performed.