This paper presents a novel robust control approach for a fully-actuated hexrotor based on Gaussian process regression(GPR). A state-space model considering aerodynamic disturbances as unknown dynamics is first built as the hexrotor dynamical model. GPR is next introduced as a learning method of the unknown dynamics. Then, a robust control method to ensure uniform ultimate boundedness on the control error is proposed. Finally, the effectiveness of the present method is shown by landing experiments near a wall.