To provide a lighting system wherein efficiency of irradiation is good, and heat dissipation capability of a light source is great.

This lighting system has a light source device 11, a flexible tube 12, and a power supply device 13. It has a light source built-in in the inside of the light source device 11, and radiates prescribed light to an object. The light source device 11 is connected to the power supply device 13 by the flexible tube 12, an exhaust fan and an exhaust vent 33 are provided in the power supply device 13, and air in the light source device 11 is exhausted to the outside of the system through the power supply device 13 to cool the light source device 11. An operator can adjust irradiation positions by directly touching the light source device 11, and the light source device 11 can be made compact.