Soltan Ahmad Shah Qajar ( 1909-1925 ) was the last ruling Shah . Among many other members of the Qajar family are The Qajar Imperial Family in exile is currently headed by the eldest descendant of Mohammad Ali Shah , Soltan Ali Mirza Qajar , while the Heir Presumptive to the Qajar throne is Mohammad Hassan Mirza II , the grandson of Mohammad Hassan Mirza , Soltan Ahmad Shah 's brother and heir .