In an endoscope system including a plurality of endoscopes including insertion portions having different diameters, each of the plurality of endoscopes includes a first bending portion subjected to bending operation to actively bend, a second bending portion passively bent by external force, a flexible tube portion having rigidity higher than rigidity of the second bending portion, and a bending portion including the first bending portion and the second bending portion. In the plurality of endoscopes, a relation among lengths of the second bending portions is set to be contrary to a size relation among insertion portion diameters.
