Steam valve

A steam valve, comprising:

• a valve seat installed in a valve casing;
• and
• a valve element coupled to a valve rod in the valve casing, and moving along an axial direction of the valve rod, in which a distance between the valve element and the valve seat is reduced when the valve rod moves in a closing direction in which the steam valve is closed, and the distance between the valve element and the valve seat is increased when the valve rod moves in an opening direction in which the steam valve is opened, wherein
• the valve element comprises:
• a first valve element part positioned in the closing direction, and including a first valve element part outer peripheral surface configured to surround the valve rod;
• and
• a second valve element part positioned in the opening direction, and including a second valve element part outer peripheral surface configured to surround the valve rod, wherein:
• the first valve element part outer peripheral surface is a curved surface formed to have a diameter increased toward the opening direction;
• and
• a diameter of boundary position between the first valve element part outer peripheral surface and the second valve element part outer peripheral surface is the same as a seat diameter of valve seat at which the valve element is brought into contact with the valve seat when the steam valve is set to a fully-closed state.