Patent ID: 8343043

Claim:
An endoscope comprising: a distal end portion provided at a distal end of an insertion portion, and including a distal end surface which faces an insertion direction of the insertion portion and an outer circumferential lateral surface which faces a circumferential direction of the insertion portion; a front-view observation window for observing an insertion direction of the distal end portion, which is provided so as to face toward the insertion direction; a lateral-view observation window for observing a circumferential direction of the distal end portion, which is formed along the outer circumferential lateral surface and has a lateral observation field of view; a light-emitting member having an emission end surface for emitting light in a distal end direction of the distal end portion; a groove portion formed on the outer circumferential lateral surface of the distal end portion so as to be longer than the emission end surface of the light-emitting member along the circumferential direction of the outer circumferential lateral surface of the distal end portion and so as to be opposed to the emission end surface of the light-emitting member, the groove portion being on a proximal end side with respect to the lateral-view observation window; a plurality of particles arranged in the groove portion and having a size sufficiently smaller than a depth of the groove portion, the particles illuminating an observation field of view side of the lateral-view observation window by scattering light emitted from the emission end surface of the light-emitting member; and a transparent infill filled between the plurality of particles in the groove portion, wherein the lateral-view observation window has a lateral field view of a wide angle larger than at least three-quarters of an entire circumference along the circumferential direction of the lateral surface of the distal end portion, and the groove portion performs lateral-view illumination over a wide range larger than the three-quarters of the entire circumference.