Vibration isolation control of buildings is important for enhancement of safety for large earthquake. The sliding mode control theory which is one of nonlinear control theory has recently received attention in the field of active control. Although the advantage of the SMC method is a simple controller design and is capable of building a robust system against nonlinear characteristics of structures or devices, the disturbance is ignored or cancelled through the matching condition. In this study, a new method of the disturbance accommodating sliding mode control is presented, in which the disturbance is taken into account by augmenting the state space and the sliding mode is defined for the augmented state space. This method is applied to a base isolation control problem of a ten-degree-of-freedom structural model with active base isolator. In order to investigate the performance of the proposed method, computer simulations were carried out, and as a result, the effectiveness of the method was shown.