An endoscope including an insertion unit includes an observation optical system (32b) arranged at an end surface (21) of the insertion unit (3) in an inserting axis direction and having a wide viewing angle used for observing a body cavity； and a plurality of illumination optical systems arranged on an axis (33LA) slanted with respect to the inserting axis direction (32LA) of the insertion unit and used when illuminating the body cavity. An illumination lens (11) of at least one illumination optical system of the plurality of illumination optical systems is a lens performed with light diffusion process.
