Abstract: An excrement disposal device includes a pair of base plates, a pair of wing plates and a disposal bag. Front and rear ends of the two base plates are pivotally attached to each other, to make an opening between the base plates variable. The wing plates are mounted on the two base plates. A top section of each wing plate is opposedly situated to face the aforementioned opening from ahead and from behind to longitudinally control the shape of the opening, thereby making the dimensions of a mouth section variable. The disposal bag is vertically inserted into the mouth section, wherein a mouth periphery of the inserted disposal bag touches a subanal area from below and can be opened and closed in accordance with the opening and closing motion of the anus.