PURPOSE: A motion sickness preventing chair is provided to detect the tilted extent when a vehicle drives on curves or moves on a sloped surface and to be able to maintain the horizontal state of the chair by the programmed calculating method. CONSTITUTION: A motion sickness preventing chair comprises a seating area (10), a back of a chair (20), a foot rest (30), a main motor (40), a first connector and a second connector, and an inclination detection sensor. The seating area maintains the horizontal state of the chair. The first and second connectors are operated so that a passenger is able to stably seat through the inclination detection. In the seating area, a motor transferable to every direction is attached, and keeps the horizon straight when the vehicle moves. Inclination detection sensors are attached to the part between the vehicle body and the wheels and 4 places of the end part of the vehicle body, and detect the inclination according to the extent of being inclined.