This machine measures the stiffness of paper, fiber, and film by the self-weight flexing method. Typical specimens are papers of small basis weight such as newspaper and thin paper. The specimen is pinched between a set of rolls and the rolls are turned slowly in both directions. The length of specimen projection from the rolls is measured when the defection angle of the specimen from one side to the other becomes 90 degrees. Based on this length, the Clark stiffness is determined. Conventionally, this test has required skilled technique and much time of operation, which would often cause inter-operator error. Aimed at solving such problems and labor saving, we have developed this tester that performs a series of operation steps automatically.