To provide a device capable of accurately detecting running-on to a step height.

This step height running-on detecting device includes a pressure sensor provided in a wheel and detecting tire air pressure, and an ECU (a running-on determining means) for determining whether the wheel runs on the step height based on a detecting signal of the pressure sensor. With this constitution, when the wheel tries to run on the step height, the tire air pressure changes so as to increase, and at this time, a pressure detecting means detects an increase in the tire air pressure, and the running-on determining means determines that a tire runs on the step height. Thus, since the step height is detected by a change in the tire air pressure of the wheel directly contacting with the step height, the step height running-on can be accurately detected.