An endoscope according to the present invention includes a bending section 12 which is bendable in a plurality of directions, and an inserting portion 2 having a distal-end portion 11 which is arranged on the distal-end side of the bending section 12 and which has an objective optical system 26 and a treatment instrument inserting channel 29. The treatment instrument inserting channel 29 is arranged in the inserting portion, and has an opening in the direction opposite the bending direction, with respect to the arrangement position of an observing optical system when the bending section is bent in the bending direction.
