An endoscope including a first bending portion that actively performs a bending action in conjunction with a bending operation in an operation portion, a second bending portion that is provided on a proximal end side of the first bending portion, and passively performs a bending action by an external force, a flexible tube portion that is consecutively connected to a proximal end side of the second bending portion, wherein a series of helical tube portions (a first flex and a second flex) are disposed in the second bending portion and in the flexible tube portion, the helical tube portion being configured such that bending rigidity at a distal end side is higher than bending rigidity at a proximal end side, a boundary at which the bending rigidity of the helical tube portions change (a boundary between the first flex and the second flex) is set to a distal end side of the flexible tube portion, to thereby prevent buckling of the bending portion and realize good insertability of an insertion portion.
