An engine-waste-heat utilization device includes a Rankine cycle which includes a heat exchanger through which cooling water coming out from an engine flows to recover waste-heat of the engine to refrigerant, an expander which generates power using the refrigerant coming out from the heat exchanger, a condenser which condenses the refrigerant coming out from the expander and a refrigerant pump which supplies the refrigerant coming out from the condenser to the heat exchanger, and a cooling water passage in which the cooling water having a higher temperature flows when the Rankine cycle is operated than when the Rankine cycle is not operated.