The castle tower of Maruoka-jo Castle has various distinct features, including decorative wrap-around verandas with high handrails, a well-lit interior compared with the other keeps among the 12 Existing Castle Towers, and slate roofs (with stone orcas) instead of clay tile roofs, which would crack in cold weather.
飾り外廻縁と高欄を有し、「現存12天守」の中では採光がよく室内が明るい点や、寒さで割れてしまう粘土瓦の代わりに石瓦が葺かれている（石の鯱も展示）ことなどの特徴がある。