Metal seal and fluid control apparatus

A metal seal that is a ring-shaped metal seal arranged between a first flat surface and a second flat surface that is parallel to the first flat surface and held by the first flat surface and the second flat surface with a pressing force as the first flat surface and the second flat surface approach each other, the metal seal comprising:

• a first end surface part arranged to face the first flat surface;
• and
• a second end surface part arranged to face the second flat surface, wherein
• the first end surface part comprises:
• a first convex part having a curved surface or a flat surface that makes contact with the first flat surface;
• and
• a first projection that is formed by being shifted in a radial direction with respect to the first convex part and that has a ridge line that makes contact with the first flat surface, and
• when the metal seal is in a natural state prior to deformation in which the second end surface part makes contact with the second flat surface and the first flat surface is separated from the first end surface part, a point where a vertical distance between the first convex part and the second flat surface is at a maximum and the ridge line of the first projection are located on a same plane that is parallel to the first flat surface.