It is a lookout-tower-style keep interconnecting a large keep, having 5 tiers, 6 aboveground floors, and 1 underground level, and three 3-tiered small keeps, with a 2-tiered, parallel Tamon-yagura (hall turret) being the largest existing castle keep in Japan.
望楼型5重6階地下1階の大天守と3重の小天守3基を2重の多聞櫓で連結させた天守連立式の天守で、日本国内最大の現存天守である。