A steering transaxle comprises: left and right drive shafts drivingly connected to respective steerable wheels; a differential gear unit differentially connecting the drive shafts to each other; a transaxle casing having an opening, the transaxle casing incorporating the differential gear unit and the drive shafts; a cover for covering the opening of the transaxle casing; a variable hydraulic motor having a movable swash plate, the hydraulic motor being provided on the inside of the cover; a motor control mechanism for controlling the movable swash plate, the motor control mechanism being provided on the outside of the cover; and a hydraulic oil port for oil supply and delivery to and from the hydraulic motor, the hydraulic oil port being provided on the outside of the cover.