PURPOSE: To provide a processing machine capable of removing certainly dust simultaneously with its generation to be generated in cutting process, without preparing a full cover which causes a large size of the processing machine as a whole.

CONSTITUTION: A holder in which the first flow hole 11 connected to a dust catcher is formed is provided at the end of a main shaft 2. An end mill provided with a vent hole in the center of an axis thereof is mounted to the main shaft 2 through the holder. The vent hole 7 has an opening 7a along cutting edges and has communication with the first flow hole 11 through the first air room 12. Dust is collected simultaneously with its generation from the opening 7a when the end mill is cutting a work.