To provide a highly efficient pre-cleaner of a simple structure.

The centrifugal dust separation device provided at an intake passage inlet of an engine and separating dust 21 in intake air is provided with an outer tube 15 having intake air pass through, a turning blade 13 giving intake air passing the outer tube 15 swirl 51, an inner tube 16 leading air flow inside of the swirl 51 to an intake port of the engine, a dust chamber 19 communicating with air flow at outside of the swirl 51, and a blower 17 sucking air in the dust chamber 19.