| For a mobile manipulator to be used in areas such as offices and houses, it is desirable that the mobile platform be small sized. In the case of a small-sized platform, the mobile manipulator may tip over when moving at high speed or executing tasks in the presence of disturbances. Therefore, it is necessary to simultaneously consider both stabilization and manipulation while coordinating vehicle motion and manipulator motion. In this paper, we first present the concept of the valid stable region to evaluate stability in the presence of disturbances. Next, we propose a method for coordinating vehicle motion planning including manipulator configuration, and manipulator motion planning including platform stability. Then, the optimal problem of vehicle motion is formulated, taking into account vehicle dynamics, manipulator workspace, and system stability. Also, the manipulator motion is derived, considering stability compensation and manipulator configuration. Finally, the effectiveness of the proposed method is demonstrated by simulation examples.