An object of the present invention is to provide a turbine external compartment, a frame for a turbine external compartment, and a method of constructing a frame for a turbine external compartment that can improve a flow of steam inside of the compartment and can enhance the rigidity of the compartment using a simple structure. A turbine external compartment according to the present invention is placed in a frame having a steel-plate reinforced concrete structure obtained by filling a space between a plurality of steel plates with concrete. The turbine external compartment includes a lower half part having a side plate part or an end plate part made of the steel plates that constitute the frame.