An engine-waste-heat utilization device includes a Rankine cycle with a heat exchanger that is configured to recover engine-waste-heat to refrigerant, an expander that is configured to generate power using the refrigerant coming out from the heat exchanger, a condenser that is configured to condense the refrigerant coming out from the expander and a refrigerant pump that is configured to supply the refrigerant coming out from the condenser to the heat exchanger by being driven by the expander, a power transmission mechanism (crank pulley, pump pulley, belt) that is configured to transmit surplus power to the engine when the expander has spare power even if the refrigerant pump is driven, a clutch that is configured to connect and disconnecting power transmission by the power transmission mechanism, and a case provided near a high-temperature part of the engine such that a shaft of the expander and that of the refrigerant pump are coaxially arranged, the clutch, the refrigerant pump and the expander are integrally housed in this order and the expander has a higher temperature than the clutch.