(15), and the present invention, rod-like to a movable sliding one tube (12) at least, is applied to a medical which is arranged between them an outer casing tube (1,2,3), the inner fixed optical tube A rigid endoscope, (6), optical observation distal end having a light emitting portion that are adjacent to distal transparent window (4), a light deflecting prism facing distal window (4) and a mirror shaft endoscope configured proximal end having a camera or adapter (22), the hollow tube nested apparatus, the distal end window outer hollow tube of two (1,3) of (4) forming a casing tube having, in the interior of the optical tube, an optical tube (15) has a (14) an optical system that transmits a light beam and having (6) movable deflecting prism in distal window, can be slid in the direction of the longitudinal axis of the endoscope at least disposed between the casing and the tube (1,2,3) optical tube (15), distal window sliding one tube (12), (4 (13) is provided with devices to), by the device, the deflection incident diffused light to the side of (6) deflecting prism faces (4) distal window can be avoided, facing (4) distal window prism (6), is supported by a rotating shaft perpendicular to the (8) to the longitudinal axis of the endoscope, a sliding tube (12) is connected to the deflecting prism (6) at the distal end, the sliding of the tube (15) The optical tube, and to cause rotation of the prism about its shaft (8), the casing tube (1,2,3) of the hollow inner tube disposed therein forming a sealed interior and leakproof completely surrounding, by its leak-proof, it is possible to sterilize the steam space surrounding the internal, slidable permanent magnet sliding of the sliding tube on the optical tube (20 , the result from the magnetic force generated by 21), where inside the sealed interior (17) to (20), and one permanent magnet is arranged outside (21) of at least one permanent magnet, at least, relates to an endoscope. [Selection Figure] Figure 2b本発明は、外側ケ
