Abstract: A device for measuring angular velocity of a rotating tire, comprising a plurality (“m” pieces) of light reflection marks (3) disposed on an outer surface of a sidewall portion (2s) of a tire (2) so as to be located on a circumference line (j) of a single circle centered on a tire axis (i), a light sensor (5) fixed to a vehicle body (4) and capable of detecting passing of the light reflection marks (3) rotating with the tire (2), and a calculation means (7) for calculating the angular velocity Vr of the tire (2) by detecting passing of the light reflection marks (3) with the light sensor (5).