To provide an exhaust heat recovery Rankine cycle system capable of enhancing exhaust heat utilization efficiency by preventing a working medium from being supercooled.

In an exhaust heat recovery Rankine cycle system 1, a working medium in a state of gas discharged from an expander is condensed by a plurality of condensers, namely, a first condenser 5, a second condenser 6, and a third condenser 7. The first condenser 5, the second condenser 6, and the third condenser 7 are connected in series, and the working medium condensed by each condenser is discharged into a condensate tank 8.