This paper studies the stabilizing control of an underactuated Furuta pendulum system subjected to an unknown matched disturbance. Firstly, the system’s dynamic model is derived using Lagrange modeling method. Through approximate linearization and a coordinate transformation, this model is converted into a standard chained form system around the zero equilibrium point. Subsequently, the disturbance is estimated in finite time by a Levant differentiator disturbance observer. And then, a robust stabilziation controller is designed using an integral sliding mode technique and the estimated disturbance value. It enables the Furuta pendulum system to be robustly stabilzied at the zero equilibrium point in a finite time. The effectiveness of our presented method is verified from numerical examples.