To provide an overturning preventive structure for a railroad vehicle that can prevent overturning of a railroad vehicle in case of an earthquake or the like.

Sidewalls 10, 11 for preventing vehicle overturning are provided on both sides of rails 6, 6 to hold the rails 6, 6 in between. The sidewalls 10, 11 for preventing vehicle overturning are located within 500 mm on the outside of a construction gauge KG and extended along the rails 6, 6 facing the side faces of the railroad vehicle 7. Consequently, when the railroad vehicle 7 is derailed and inclined due to the earthquake or the like, the railroad vehicle abuts (collides) against the sidewalls 10, 11 for preventing vehicle overturning, and supported by the sidewalls 10, 11 so as to be prevented from further inclination. Overturning of the railroad vehicle 7 can thereby be prevented beforehand.