Abstract: A viewer for inspecting the condition of an end face of an optical fiber which has been cleaved, while the fiber is still in the cleaving device. The viewer takes the form of a pocket-type microscope having a cylindrical body with an eyepiece at one end and an objective lens at the other end, and an adaptor at the end of the body having the objective lens. The adaptor has a plurality of legs having notches therein forming seats which are specially adapted to be mounted on fiber-supporting pads of the cleaver. The adaptor is removable from the body so that different adaptors may be used for different cleavers. The body fits in a socket of the adaptor which may be disposed at an angle with respect to the legs to allow oblique viewing of the fiber end face while it is still in the cleaver. The viewer may optionally be used with an inspection tray having a trunnion at one end, the adaptor of the viewer being designed to pivotally mount to the trunnion, allowing viewing of the fiber end face at any angle.