An instrument (1; 61; 101; 201; 301; 301a; 500; 600) for an endoscope includes a first insertion portion (10; 71; 120; 206; 313) having an base end to which an operation section is connected; a first offset portion (11; 72; 130, 135; 205c; 312, 320) extending outward from an axis of the first insertion portion; a second insertion portion (12; 73; 140, 145; 205d; 325) having a base end joined to the first offset portion and an element extending parallel to the axis of the first insertion portion; a second offset portion (14; 74; 155, 160; 205e; 330, 341) which is joined to a head of the second insertion portion and reaches an extension of the axis of the first insertion portion; and a third insertion portion (16; 75; 165; 209; 343) which is joined to the second offset portion and has a portion arranged on an axis which is substantially the same as at least a part of the axis of the first insertion portion. An inner hole is formed through the first insertion portion, the first offset portion, the second insertion portion, the second offset portion, and the third insertion portion.