An insertion device and an endoscope which are inserted and extracted through a small incision and have multiple functions. A device body has grip forceps as a treatment means. A first folding back section and a second folding back section are provided at a distal portion of the device body such that the first and second folding back sections are aligned in a row in the longitudinal direction of the device body. The first folding back section and the second folding back section respectively have image obtaining means. An operation means can move the first folding back section to a folded back position in which the first folding back section is folded back relative to the second folding back section, and can also move the second folding back section to a position in which the second folding back section is folded back relative to the device body.