This mucosa separation apparatus includes a first insertion portion inserted to the interior of a subject, an expansion portion disposed on a head portion of the first insertion portion, and which expands by infusion of a fluid, a passage formed within the first insertion portion and connected to the expansion portion, for supplying the fluid to the expansion portion, and a curving portion which makes a head portion of an instrument inserted to the interior of the subject curve with respect to a part of the instrument which is closer to a base portion of the instrument than the head portion thereof.
