Ablation system

[Solution] An ablation system 10 has an ablation device 11 in which a balloon 21 is provided on the distal end side of a shaft 22 and an in-side tube 27 causing a fluid to flow into the balloon 21, the internal space of the shaft 22 causing a fluid to flow out of the balloon 21, and an optical fiber 29 guiding laser light into the balloon 21 are individually provided along the shaft 22, a laser light generating unit 12 emitting laser light to the optical fiber 29, and a fluid returning unit 13 returning a fluid into the internal space of the balloon 21. The ablation device 11 has a reflector 33 reflecting laser light emitted from the optical fiber 29 in the balloon 21, in which the reflector 33 is movable along the axial direction 191 in the balloon 21 and is rotatable in the axial direction 101 as the axis line.