An
exhaust gas throttle valve disposed in the exhaust
system of an engine, wherein the center axis of rotation of a valve shaft 5 is set at a position deviated from the center axis of the
exhaust gas passage, and two recessed portions 11 are symmetrically formed in the circumferential portion of a valve body 4 by
cutting the surface thereof. The positions where the recessed portions 11 are formed are on the side of the center axis of the
exhaust gas passage beyond the center axis 12 of rotation, and at where the
peripheral portion of the valve body 4 faces the edge portions 9 where
insertion holes 8 for the valve shaft 5 are opened in the exhaust gas passage. At these positions, the distance is a minimum between the
peripheral portion of the valve body 4 and the edge portions 9. The recessed portions 11 work to increase the gap relative to the edge portions 9 at that positions. It is therefore made possible to approximate the
peripheral portion of the valve body 4 to the tubular wall of the exhaust gas passage 2 when the exhaust gas
throttle valve is closed preventing the valve body 4 and the edge portions 9 from coming in contact together despite of the
thermal expansion.