This paper presents a control technique for stabilizing an inertia wheel pendulum system using multiple sliding surface control. The inertia wheel pendulum is an underactuated mechanical system with one control input and two degrees of freedom. The paper first develops a dynamic model using Euler-Lagrange equations of motion. It then designs a controller based on multiple sliding surface control and analyzes the stability of the closed-loop system. Simulation results demonstrate the effectiveness of the proposed control method.