The influences of machine factors and material factors on the needle temperature due to the frictional heat generation between fabric and needle during sewing was investigated and the heat losses of needle due to the convection heat transfer was discussed. It was found that the needle size had very little effect on the needle temperature but the mediumball point needle and super needle were effective in reducing heat generation. The approximate values of convection heat transfer coefficient of needles decrease with the increase in needle size. The sewing speed and number of fabric layers were apparently the largest influence of heat generation of needle. In the case of using sewing thread, the needle temperature was decreased remarkably.