The utility model relates to a driving mechanism for a tattoo machine, wherein a motor is arranged inside a body to drive a driving mechanism, and the driving mechanism drives the needle head of a needle assembly to move reciprocally with respect to the body.The transmission mechanism includes a first assembly, a second assembly and a ball. The surface of the first assembly is provided with at least one guide groove, while the surface of the second assembly is provided with a limit hole. When the first assembly is installed inside the second assembly, the ball is installed in the guide groove and positioned in the limit hole.When the motor drives the first assembly to rotate and the ball is positioned at the first return end of the guide groove, the ball guides the first assembly to drive the needle to extend toward the outside of the body.When the ball is positioned at the first and second return ends of the guide groove, the ball guides the first assembly to drive the needle to retract into the body.Through the structural design of the ball and guide groove of the transmission mechanism, the axial rotation can be used to drive the linear reciprocating displacement of the needle assembly.一種用於紋身機之傳動機構，在一機體內部設置有一馬達來驅動一傳動機構，並由傳動機構帶動一針組件的針頭相對於機體往復位移。傳動機構包括有一第一組件、一第二組件及一滾珠，第一組件表面開設有至少一導槽，而第二組件表面開設有一限位孔，當第一組件裝設於第二組件內部時，滾珠被裝設在導槽內且定位在限位孔之中。當馬達驅動第一組件旋轉而史滾珠位在導槽的一第一迴流端時，滾珠導引第一組件帶動針頭朝機體外部伸出。當滾珠位在導槽的一第二迴流端時，滾珠導引第一組件帶動針頭往機體內部縮入。藉由傳動機構的滾珠及導槽的結構設計，可利用軸向旋轉運動來帶動針組件的直線往復位移。
