A steam valve includes a valve body having a valve seat in a steam channel, a valve stem configured to close the steam channel by coming in contact with the valve seat and to open the steam channel by moving from the valve seat and a guide portion configured to slidably guide the valve stem in a moving direction thereof. The guide portion has a guide body that encloses the valve stem from a radial outer side of the valve stem and a guide bush that is detachably fixed inside the guide body, has an inner surface which abuts and slides on an outer circumferential surface of the valve stem, and is formed of a material having corrosion resistance.