An endoscope 1 includes: an insertion portion 31 including an image pickup section 33 and an illumination section 34 in a distal end portion 32 thereof and a light guide 13 inserted through an inside of the insertion portion 31, the light guide guiding illuminating light from a light source apparatus 24 connected to a proximal end portion side to the illumination section 34, the light guide having a numerical aperture of 0.46 to 0.90, wherein the light guide 13 includes fibers 10 made of a glass not containing lead, and an amount of light of 380 to 750 nm after an X-ray resistance test in which recovery processing of guiding light of 64 lumen/mm 2 for 600 minutes is performed after irradiation with an X-ray of 2.5 Gy is no less than 67% of the amount of light before the X-ray resistance test, and a blue color light amount ratio which is (an integrated amount of light of 380 to 470 nm/an integrated amount of light of 470 to 580 nm) after the X-ray resistance test is no less than 60% of a blue color light amount ratio before the X-ray resistance test.
