To provide a vehicle speed computing device determining the correct vehicle speed from the angular velocities of the wheels and the internal pressures of the tires.

A vehicle 10 is equipped with pressure sensors 25-28 for detecting the internal pressures P(n) of the tires n(n=1 to 4) and wheel velocity sensors 21-24 for detecting the angular velocities ωn of the wheels (n). The device calculates the changing rate DP(n) of the dynamic load radius based on the difference ΔTP(n) between the reference pressure PS(n) and the internal pressures P(n) of the tires respectively detected by the pressure sensors to determine the vehicle speed computing wheel speed SPDH(n) based on the angular velocities ωn of the wheels respectively detected by the wheel speed sensors and the DP(n). The vehicle speed SPDH is calculated from the SPDH(n) to be outputted to a speed meter 19.