Abstract: An automatic tensile test apparatus includes an output device which supplies an elongation data of the specimen to the data processor in cooperation with means to optically detect said elongation, means to electrically detect said tension of said specimen and supply it to the data processor, and a device which detects the break of said specimen. Said output device generates a signal for causing the elongation strain and the tensile stress to be loaded into the data processor so as to correspond to each other. The break detector provides a break signal to the output device and the tension detecting means.