This is a test tube type air heating aging tester for evaluating the heat aging resistance of vulcanized rubber and thermoplastic rubber through air heating. To eliminate the effects of additive migration and the like, a maximum of four test pieces are placed in separate test tubes and heated at a specified temperature for a specified time. Afterwards, properties such as tensile strength, elongation at break, tensile stress, and hardness are measured, and the changes from the values before heating are determined.