An endoscope bending device includes an operation wire which includes a wire proximal end movably provided in an inner peripheral groove of a pulley, and a wire distal end connected to a bending section, the operation wire extending into an endoscope insertion section after being wound around an outer peripheral groove or the inner peripheral groove in a neutral condition in which the bending section is not bent. The endoscope bending device includes a slack absorbing portion which is configured to absorb the slack of the operation wire by moving the wire proximal end of the operation wire in the inner peripheral groove in a direction opposite to a discharging direction of the operation wire during the operation of discharging the operation wire from the neutral condition.
