In a frictional drive vehicle, a load acting on the vehicle such as the weight of a rider is converted into a force that urges two frictionally engaging parts (3L, 3R, 25) toward each other. Thereby, the contact pressure between the two frictionally engaging parts is maintained at an optimum level under all conditions. A weight of a rider may be transmitted to a drive member that frictionally engages a main wheel via a four-link parallel link mechanism (40, 50).