A motorized wheelchair having transmission rollers to transmit the rotation of rear wheels to front wheels while being disposed at a transmission position between circumferential surfaces of front and rear wheels, a roller supporting arm for rotatably and oscillatingly supporting the transmission rollers in the front-rear direction of the wheelchair, and transmission roller pressure-contact springs for urging the roller supporting arm in a direction of the transmission position. An operation lever constrains the roller supporting arm in an interlocking manner in the direction away from the transmission position when being at the regular position, and releases the constrains when the operation lever being at the working position so as to allow the transmission rollers to be disposed at the transmission position.