An annular metal gasket for sealing a space between members by being pressed in the vertical direction in a state of being mounted between the members, the metal gasket comprising an annular outer ring having a substantially C-shaped cross-section and having a circumferential-direction opening formed therein, and an annular inner ring fitted inside the outer ring. The inner ring is formed so as to have a polygonal cross-section. Bend parts having an inner angle larger than 180° are formed between the upper corner part and the inner- and outer-circumference-side corner parts; and between the lower corner part and the inner- and outer-circumference-side corner parts.