An endoscope 1 of the present invention includes an operation section 3, an insertion section 2, a treatment instrument insertion channel 17 through which an elongated treatment instrument 30 is inserted, a treatment instrument elevation base 21, and a treatment instrument An observation window 25 disposed on the side of the operation section 3 in the longitudinal direction of the insertion section 2 with respect to the elevator base 21 and a treatment tool 30 projected and oriented by the treatment instrument elevator base 21 when the treatment instrument elevator base 21 is tilted And a restricting surface 31A of the restricting portion 31 that regulates the angle of protrusion to the outside of the distal end portion 5. A line O1 connecting the treatment instrument elevator base 21 and the observation window 25 is formed such that the insertion portion 2 is inserted And the regulating surface 31A is provided so as to be positioned on a line segment connecting the treatment instrument elevator base 21 and the observation window 25 when the observation window 25 is viewed in a face-to-face manner Has been done.本発明の内視鏡1は、操作部3と、挿入部2と、細長い処置具30を挿通させる処置具挿通チャンネル17と、処置具起上台21と、挿入部2の先端部5で処置具起上台21よりも挿入部2の長手方向の操作部3側に配置される観察窓25と、処置具起上台21を傾けた際、処置具起上台21によって方向付けられて突出した処置具30に接触し、先端部5の外部に突出する角度を規制する規制部31の規制面31Aと、を具備し、処置具起上台21と観察窓25とを結ぶ線O1は、挿入部2が挿入される方向の長手軸Oと略平行であり、規制面31Aは、観察窓25を正対視したときに、処置具起上台21と観察窓25とを結ぶ線分上に位置するように設けられている。
