To improve the economic performance and efficiency, stop an electric hydraulic composite transmission in a stable condition, and simplify a drive system thereof by electrically separating a motor connected with an input shaft of a differential hydraulic motor, bringing an incorporated brake into a braking condition, and supplying fluid into an external hydraulic port from an external hydraulic pump.

An output shaft of a motor 67 is connected with an input shaft 14 to bring the motor 67 into an electrically open and idling condition. Control pressure is applied to a brake pressing piston 62, a brake slide plate 64 is compressed, and a cylinder block 22 is braked to bring it into a retrained condition to a casing 73. Fluid is supplied into external hydraulic ports 85, 86 by a hydraulic pump. Fluid passes a slide face 28 of a rotary port and a group of pistons 30 is connected to either port in an external chamber or internal chamber of a ring type change-over valve 26 driven by an eccentric core shaft 17 connected with a first shaft 16 by dividing the group into an advance group and retracting group by a change-over valve incorporated into a cylinder block 22 in a stationary condition. An oblique plate 53 rotates at a speed proportional to a fluid supply rate to the external hydraulic ports.