To provide a rotary machining device which easily supplies mists to a processed portion.

This rotary machining device for doing processing while supplying oil mists 90a cooling heats generated by lubrication and processing between a tool 30 and a workpiece from mist supply holes 31 provided in the tool 30, comprises: an oil mist generating device 60 generating and supplying the oil mists 90a; a main spindle member 10 rotating while holding the tool 30 and having a mist delivery pipe 16 communicating the mist supply holes 31 with the oil mist generating device 60 and rotating together with the tool 30; an oil mist charging device 70 charging the oil mist 90 supplied from the oil mist generating device 60 before the mists reach the mist delivery pipe 16; and a delivery pipe charging device 80 charging the mist delivery pipe 16. The oil mist charging device 70 and the delivery pipe charging device 80 charge the oil mists 90 and the mist delivery pipe 16 at the same polarity.