The endoscope comprises an optical focusing and zooming device (3), motion imparting members (4) operable on the optical device (2), transducer members (5) located downstream from the optical device (3) and designed to convert an optical flow into an electric signal, lighting members (6). A control and monitoring unit (8) receives signals representative of optical zoom degrees and is connected to the motion imparting members (4) to actuate the latter. The optical device (3) comprises a first set of lenses (8), a second set of lenses (9) adapted to be moved by the motion imparting members (4) for changing the optical zoom, a third set of lenses (10) adapted to be moved by the motion imparting members (4) for focus adjustment, a fourth set of lenses (11) for focusing the optical flow on the transducer members (5); the distance between the first (8) and the fourth (11) sets of lenses being unchangeable.