An endoscope comprising: an insertion portion including a bending portion including a plurality of bending pieces formed in a circular ring shape such that bending pieces adjacent to each other are rotatably connected to each other with the phases of the adjacent bending pieces being changed by 90 degrees with respect to each other to bend in a first direction (U-D) and a second direction (L-R) orthogonal to the first direction; said insertion portion further including a flexible tube portion provided at a rear end of the bending portion in a linked manner; a light guide fiber bundle inserted in the insertion portion; and a guide coil through which a raising wire configured to transmit a rotation raising operation of a raising stand for raising a distal end portion of a treatment instrument is inserted, a rigidity adjusting coil configured to adjust a rigidity of the flexible tube portion, and a treatment instrument channel, the guide coil, the rigidity adjusting coil and the treatment instrument channel being inserted in the insertion portion and formed to be more rigid than the light guide fiber bundle, wherein the flexible tube portion is sectionalized into four quadrants (Q1-Q4) by coordinate axes (x, y) passing through two respective rotational centers of respective bending pieces at the time that the bending portion is bent in the first direction (U-D) and in the second direction (L-R), the four quadrants (Q1-Q4) being a first quadrant, a second quadrant adjacent to the first quadrant, a third quadrant adjacent to the second quadrant, and a fourth quadrant adjacent to the third quadrant and the first quadrant, characterized in that a center of the axis of the guide coil is disposed in the first quadrant, a center of the axis of the rigidity adjusting coil is disposed in the second quadrant, a center of the axis of the light guide fiber bundle is disposed in the third quadrant, and a center of the axis of the treatment instrument channel is disposed in the fourth quadrant. an insertion portion including a bending portion including a plurality of bending pieces formed in a circular ring shape such that bending pieces adjacent to each other are rotatably connected to each other with the phases of the adjacent bending pieces being changed by 90 degrees with respect to each other to bend in a first direction (U-D) and a second direction (L-R) orthogonal to the first direction; said insertion portion further including a flexible tube portion provided at a rear end of the bending portion in a linked manner; a light guide fiber bundle inserted in the insertion portion; and a guide coil through which a raising wire configured to transmit a rotation raising operation of a raising stand for raising a distal end portion of a treatment instrument is inserted, a rigidity adjusting coil configured to adjust a rigidity of the flexible tube portion, and a treatment instrument channel, the guide coil, the rigidity adjusting coil and the treatment instrument channel being inserted in the insertion portion and formed to be more rigid than the light guide fiber bundle, wherein the flexible tube portion is sectionalized into four quadrants (Q1-Q4) by coordinate axes (x, y) passing through two respective rotational centers of respective bending pieces at the time that the bending portion is bent in the first direction (U-D) and in the second direction (L-R), the four quadrants (Q1-Q4) being a first quadrant, a second quadrant adjacent to the first quadrant, a third quadrant adjacent to the second quadrant, and a fourth quadrant adjacent to the third quadrant and the first quadrant, characterized in that a center of the axis of the guide coil is disposed in the first quadrant, a center of the axis of the rigidity adjusting coil is disposed in the second quadrant, a center of the axis of the light guide fiber bundle is disposed in the third quadrant, and a center of the axis of the treatment instrument channel is disposed in the fourth quadrant.