The present invention is to provide an endoscope flexible tube that makes it possible to secure larger internal space while maintaining assemblability. For the object, the endoscope flexible tube according to the present invention includes: a spiral tube 11 configured such that a belt-like plate is spirally wound an inner cylindrical member 14 disposed inside an end part 21 of the spiral tube and an outer cylindrical member 15 that is disposed outside the end part of the spiral tube and holds the end part of the spiral tube between the outer cylindrical member and the inner cylindrical member. The inner cylindrical member is disposed inside the end part of the spiral tube to make a diameter D1A of the end part of the spiral tube larger than a diameter D1 of a part that is different from the end part of the spiral tube.