A stationary blade and a steam turbine capable of reducing self-excited vibrations with a simple configuration are provided. A stationary blade has a cavity, extending in a blade-width direction, formed therein and slits communicating between the cavity and the outside. A wave-shaped plate spring that is in sliding contact with at least one of a pressure-side member and a suction-side member is provided between the pressure-side member, which is a portion on the pressure side of the cavity, and the suction-side member, which is a portion on the suction side of the cavity. When the stationary blade is elastically deformed, the wave-shaped plate spring causes friction between itself and at least one of the pressure-side member and the suction-side member. This friction attenuates relative positional displacement between the pressure-side member and the suction-side member. Thus, self-excited vibrations occurring at the stationary blade can be reduced.