This paper aims to analyze fundamental dynamic characteristics of tilting railway vehicle using variable link mechanism for compensating both lateral acceleration that passengers feel and wheel load imbalance between inner and outer rails. In this report, geometric relations between the center of rotation, the center of gravity, and the positions of all four links of tilting system are analyzed. Then, equations of the pendulum motions of railway vehicle body with four-link mechanism are derived. This paper theoretically discusses about the geometrical shapes of link mechanism that can provide zero lateral acceleration and zero wheel load fluctuation simultaneously. Then, “perfect tilting condition”, which is the control target of feedforward tilting control, is derived by linear equation of tilting motion.