An endoscope insertion portion of the invention is inserted into a body cavity and includes a distal end portion at a distal end part, the endoscope insertion portion having: a plurality of observation windows having different outer diameters for leading incident light to a plurality of image pickup portions, and disposed on a distal end surface of the distal end portion and an air/water feeding portion for spouting out a gas or liquid toward the plurality of observation windows, and disposed to the distal end portion, wherein one of the plurality of observation windows having the largest outer diameter is disposed on the distal end surface at a position closest to the air/water feeding portion than the other of the plurality of observation windows. The endoscope insertion portion thus can efficiently remove filth or the like adhered on outer surfaces of a plurality of observation windows, and in particular, secure fine observation field of view of an image pickup portion frequently used.
