Abstract: An engine exhaust gas cleaning apparatus is provided to suppress EGR ratio fluctuations when the excess air ratio is adjusted and thereby stabilize the engine operating performance.

Abstract: An adjusting mechanism (56) is provided to produce an anti-overturning moment to reduce an overturning moment acting on an orbiting scroll (26) during its revolution in a revolving-angle area in which the overturning moment becomes a certain value or more. Accordingly, revolution movement of the orbiting scroll (26) can be made stable by changing a pressing force of the orbiting scroll (26) against the fixed scroll (22) according to fluctuation of the overturning moment due to the revolution of the orbiting scroll (26), thereby improving the compression efficiency of a scroll-type compressor (1).