It was found in the 1st report that sintered carbide K type is most suitable tool material for lathe turning of titanium alloy because of its large thermal conductivity and small affinity for titanium alloy. From this fact, sintered carbide K 10 as tool material was used in this experiment. we have tried to see how machinability of titanium alloy is effected by hot machining, using two methods, sectional electric resisting and gasoline burner heating. To compare with titanium alloy, carbon steel S45C on which built up edges grow easily has been machined in same cutting condition as titanium alloy. The results are as follows. (1) When titanium alloy is machined with sintered carbide tool K 10,being heated by sectional electric resisting heating, cutting resistance is reduced. But tool life decrease because the cutting edge is softened by high cutting temperature. (2) When alternating current is used as heating current, owing to cycle of it, variation of cutting resistance and surface roughness become larger, these tendencies are particularly remarkable in titanium alloy. (3) When the gasoline burner heating is used, the work is stisfactoly heated unlike in sectional electric resisting heating, and accordingly variation of cutting resistance and surface roughness become smoller.