An endoscope system 1G includes a flexible endoscope 10, a treatment tool 20, and a power supply 30. The flexible endoscope 10 has a power transmission unit 19 including a first coil 18 wound around a flexible channel 14 to convert power from the power supply 30 into an AC magnetic field, and the treatment tool 20 has a power reception unit 29 including a second coil 28 arranged in a position of receiving power most efficiently in a state where a treatment unit 22 projects from an opening 14B.
