PURPOSE: To measure an errorless and precise tire slip angle in the ground- touching point of a tire on the basis of a detection value obtained by detecting line-direction velocities on the central line of the tire and on the shaft line of the tire.

CONSTITUTION: This measuring apparatus is featured by comprising a one- dimensional speed sensor A101 which is arranged in an arbitrary position on the central line of a tire and which detects the speed in the central-line direction of the tire, with a one-dimensional speed sensor B102 which is arranged in an arbitrary position on the shaft line of the tire and which detects the speed in the shaft-line direction of the tire and with an angle operation circuit 203 which operates a tire slip angle on the basis of information on the individual speeds detected by the one-dimensional speed sensor A101 and the one- dimensional speed sensor B102.