For the study of variation in cutting temperatures by the measuring techniques in the previous report, cutting tests were conducted under the following conditions:cutting speed 100-600m/minfeed 0.04-0.32mm/rev.depth of cut 1mm, 3mmThe specimens used for the tests were billets of the following 7 sorts of commercial aluminum alloys.2S, 11S, 17S, 56S, 63S, Lo-Ex, and Al-23%Si cast alloyThe following results were obtained.(1) The highest temperature measured in the former alloys was 470°C (for 580m/min, 0.32mm/rev. and 3mm) in 56S, and the lowest was 320°C (for 560m/min, 0.32mm/rev., and 3mm) in 2S.(2) The values of the temperature were arranged in descending order as follows.56S>17S>11S>63S>2S(3) The highest cutting temperatures in Al-23%Si alloy and Lo-Ex were about 480 and 410°C (both for 320m/min, 0.32mm/rev., and 1mm), respectively.(4) The rising rates of cutting temperature in the above alloys with respect to the change of cutting speed or feed were arranged in descending order as follows.With respect to cutting speed 11S>17S>63S_??_56S>2SWith respect to feed 11S_??_17S>56S>63S>2S(5) Isothermal lines were experimentally determined by cutting temperatures measured in the above 7 sorts of commercial aluminum alloys.