The 30-year old or older persons with Koshaku (公爵) or Koshaku (侯爵) became permanent members of Kizokuin, persons with Hakushaku, Shishaku or Danshaku elected as seven-year-term members from among the members; they were regarded as "loyal hedge guarding the Imperial family."
30歳以上の公侯爵議員は終身、伯子男爵議員は互選で任期7年と定められ、「皇室の藩屏」としての役割を果たすものとされた。