<p>The automotive tire (T) being measured is loaded in advance by the load applying means (24), and the drum (21) is driven to rotate the tire. A displacement of the rotatable shaft (22) produced in response to a variation in the radial force acting between the tire and the drum is detected as a displacement of the movable member (23) which is in turn indicated as the radial force variation generated on the tire. Thus, the apparatus can measure a radial force variation with precision under a condition approximating an actual running condition of automobiles.</p>
