A bending operation mechanism of the endoscope is an operating section to operate a bending section, and a boot section to cover the main body of the operating section in a watertight manner by causing a tiltable operating lever provided at the frame section to pass through the boot section, includes a watertight fixing portion on its periphery. The endoscope includes a first fixing member engaged with the locking section of the frame section and locked unrotatably in the watertight fixing portion of the boot section to press the watertight fixing portion from an outer periphery side such that the watertight fixing portion is made watertight, and a second fixing member screwed with the frame section to fix the first fixing member on the frame section.