PURPOSE: To provide an internal combustion engine equipped with a supercharger, with which the capacity of the supercharger can be made small by equalization of the requisite supercharge amount during one revolution of the engine and which can be constructed in a small size.

CONSTITUTION: An internal combustion engine 1 is equipped with a supercharger 30 driven by the exhaust gas, wherein a pressure accumulating chamber 40 at least larger than the piston stroke capacity of one cylinder is installed in the air feed passage 16b situated between the supercharger 30 and combustion chamber 7, and a check valve 18 is installed upstream of this pressure accumulating chamber 40.