PURPOSE: To block entanglement of chips in an automatic chip discharger for machine tool, by providing plural stages of concentrically rotatable spirals such that the rotary speed will increase as the stage will advance while reversing the rotary direction alternatively.

CONSTITUTION: Cutting oil and cutting chips are flowed over an oil pan 7 of machine table 5 and led through the funnel through section 23 of oil tank 21 below a chip discharge tube 25. The inclined chip discharge tube 25 is provided with first and second spirals 29, 31 in two steps to be rotatable concentrically and independently. In other word, the first spiral 29 located at the lower portion of inclination will drive through a tubular shaft 22 of second spiral 31 located at the upper position by means of a rod shaft 35 and arranged such that the spiral 31 at the rearer stage will rotate with higher speed while reversing the rotary direction between the adjoining spirals. Consequently, under carrying of chips through the discharge tube 25, the rear stage spiral will produce such function as to block entanglement of chips resulting in automatic blockage of clogging of discharge tube.