A bending operation mechanism for endoscope according to the invention includes: a bending operation member to which a bending wire for driving a bending portion of an endoscope, the bending operation member being rotationally operated to pull the bending wire in a rotation direction a rotator coupled to the bending operation member and configured to be rotationally driven by rotation operation of the bending operation member a reduction gear mechanism that reduces rotation of the rotator and a biasing mechanism that applies a biasing force in a rotation direction to an output gear in the reduction gear mechanism.