Apparatus for measuring stress of viscoelastic material

An apparatus for measuring stress of viscoelastic material in which a rotational die (81) and a torque detecting die (82) are provided, and an outer cylindrical die (83) is provided around the torque detecting die, the diameter of the rotational die (81) being arranged to be larger than the diameter of the outer cylindrical die (83), and the surface forming one part of a sample chamber has such a configuration that a slipping of the sample contained in the sample chamber is prevented, so that a shearing speed having no disorder can be given to the sample mounted all over the surface, forming the sample chamber, of the torque detecting die. Furthermore, in the apparatus according to the invention, since the torque detecting die (82) and the outer cylindrical die (83) provided therearound are arranged to be rotated in the same direction by the same angle in accordance with the shearing stress given by the sample, it is possible to detect correctly the counter-torque given by the sample without being influenced by a seal provided between the torque detecting die and the outer cylindrical die.