The plastic behavior in pure titanium which was rate sensitive material and aluminum alloy AS052 which were different crystal grain sizes under tensile load, were examined by using infrared thermography. Local plastic energy convert into thermal image on the specimen surface by this device and the heat generation distributions were calculated from these measured a series of thermal images, that is, the local plastic beha­viors were obtained as the image of temperature rise. This study showed that Infrared thermography was an effective device by non-contact method for evaluating macroscopic local plastic deformation.