A drive system for a hinged gate of a vehicle, which includes: a motor unit, a rack and pinion mechanism, a link member connected to a point of the hinged gate, and a shaft member fixed to the rack, to which the link member is rotatably connected. The motor unit includes a motor, gears, and a casing accomodating the gears. The rack and pinion mechanism includes a pinion driven by the motor unit and the rack movably supported on the casing of the motor unit. The casing has a guide casing, which extends in a longitudinal direction of the rack. The guide casing is formed to have a closed section surrounding the shaft member and is provided therein with a guide member configured for guiding the rack.