An endoscope includes an insertion portion having a bendable portion an operation portion from which the insertion portion extends a first bending operation knob arranged on a surface of the operation portion and including depressions and first protrusions, to bend the bendable portion in a first direction when rotated and a second bending operation knob arranged over the first bending operation knob and including depressions and second protrusions, to bend the bendable portion in a second direction when rotated. A length of the second protrusion from a center of rotation to a tip portion is longer than a length of the first protrusion from the center of rotation to tip portions of the first protrusions, and the second protrusion has a depression near a projection of a circular orbit of rotation of each tip portion of the first protrusions onto a surface facing the first bending operation knob.
