To provide an oil mist supply device for a machine tool capable of improving efficiency in the work machining work by quickly supplying the oil mist to a machining part of the work when starting machining of the work.

A storage container 32 is provided with an oil mist generating unit 34. An oil mist storage space 42 formed in an upper part of the storage container 32 and an oil mist supply passage 26 formed in a machining head 10 are made to communicate with each other through an oil mist supply pipe 45. A base end part of the oil mist supply pipe 45 is provided with a solenoid opening/closing valve 48. The oil mist generating unit 34 is previously operated by an operation signal from a control device 51 to generate and storage the oil mist 33a in the storage space 42 of the storage container 32. Simultaneously with a start of the work machining operation, an opening operation signal is output from the control device 51 to the solenoid opening/closing valve 48 to supply the oil mist 33a inside the storage space 42 to the oil mist supply passage 26 of the machining head 10, and the oil mist 33a is injected to the work from a tip of a tool 15.