NOVELTY - The system (A) has Rankine circuit (12) for converting heat energy of working fluid into torque in which expansion unit (20) in which output is possible, and condenser (22) are inserted sequentially. A power transmission unit (30) for input-outputting torque between exteriors is connected with drive shaft (72) with which pump unit (16) is connected. A check valve is inserted by portion of the Rankine circuit and extended between pump unit and heaters (18). A circuit on-off valve is inserted by portion of the circuit and extended between the heater and the expansion units.    USE - System for waste heat utilization of internal combustion engine of vehicle.    ADVANTAGE - The motive power from the outside can be stored in the portion of the circuit ranging from the check valve to circuit on-off valve as pressure energy by closing the circuit on-off valve and the conserved pressure energy can be converted into torque in expansion unit by opening the circuit on-off valve. The motive power from the outside can be conserved in forms other than electric power according to condition. The fluid machine can be operated independently, without receiving the motive power from the outside when the torque which generated in the expansion unit is large enough. The electric power generation efficiency can be increased. The pressure drop of the portion of the circuit which extended between circuit on-off valve and the expansion units can be prevented, so that the expansion unit cannot be operated in state like vacuum pump. The increase of the consumption motive power of expansion unit can be suppressed, and the motive power from the outside can be preferentially converted into pressure, and conserved even when the circuit on-off valve is closed. The pressure prevention section is comprised by easy structure. The electric power generation amount can be decreased and the driving torque of the electric power generation unit can also be suppressed while conserving the pressure energy. The electric power generation amount can be increased, the driving torque of the electric power generation unit can be increased, and the braking force to the engine can be increased at the time of braking of vehicle, and deceleration.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating the structure of the system for waste heat utilization of vehicle. (Drawing includes non-English language text)    Rankine circuit (12)    Pump unit (16)    Heater (18)    Expansion unit (20)    Condenser (22)    Power transmission unit (30)    Drive shaft (72)    System for waste heat utilization (A)