Abstract: The invention refers to an endoscope head comprising an endoscope head body, in which at least one working channel is formed, wherein an Albarran lever capable of being pivoted is provided at the distal working channel end portion. The Albarran lever can be attached at and removed from the endoscope head body.

Abstract: An illumination optical system is formed into a substantially U shape or a partial shape of the substantially U shape as a cross-sectional shape viewed from a distal end side of a longitudinal axis such that an observation optical system is arranged inside, and has a plane as an incidence surface on which light directed toward the distal end side from a proximal end side along the longitudinal axis is incident, a plane as an emission surface from which the light is emitted as illumination light toward a subject, and a reflection surface which is inclined to direct the light incident on the incidence surface toward the emission surface when viewed from the distal end side of the longitudinal axis.

Abstract: An endoscopic treatment tool includes a sheath; a treatment portion capable of protruding and retracting from a distal end of the sheath; a manipulation main body; a slider which advances and retracts in a longitudinal axis direction to cause the treatment portion to protrude and retract from the sheath; a first locking mechanism which locks the slider at a position at which the distal end of the treatment portion is accommodated in the sheath in accordance with a retracting manipulation of the slider; a second locking mechanism provided at further distal side than the first locking mechanism and restricts advance of the slider by being locked to the manipulation main body; a fixing mechanism provided in the second locking mechanism and fixed to the manipulation main body by sliding; and a restricting portion which restricts fixing of the fixing mechanism to the manipulation main body.