To reduce the projection of a swash plate servo mechanism in the radial direction, and to make a hydraulic continuously variable transmission compact, a swash plate plunger pump includes a pump casing provided with an input driven gear. A pump cylinder and a motor cylinder are connected to a transmission output shaft, and a motor pivot member provided with a motor swash plate member is supported to be pivotally movable. A motor servo mechanism includes a ball screw shaft, a ball nut to which an end portion of the motor pivot member is connected, and a swash plate control motor to rotate the screw shaft. A swash plate control motor, located on the side of a hydraulic pump relative to the input driven gear, is mounted to the outside surface of a transmission housing close to the center axis side of a transmission output shaft.