To provide a vapor generation system of high energy efficiency.

This vapor generation system comprises a supply passage 20 in which a heated medium flows, and a heat pump 10. The heat pump 10 has a heat absorbing portion 11 arranged in the flowing direction of an operation medium, a compressing portion 12, a first heat radiating portion 13A, a second heat radiating portion 13B, and an expanding portion 14. The heated medium in the supply passage 20 is heated by the second heat radiating portion 13B and then by the first heat radiating portion 13A of the heat pump 10.