A blowout is when excreta passes between the face plate of a stoma apparatus and the skin and then leaks to the outside. When a blowout occurs, clothing can become soiled and it can cause problems for people nearby, and because blowouts can become a hindrance to social life and social advancement, blowouts are a serious concern for many ostomates. The present invention addresses the problem of preventing the external scattering of excreta due to a blowout. In the present invention, an attachment means (90) is provided so that a take-in hole (83) is formed between the attachment means and the outer circumference of a face plate (12), and an auxiliary accommodation bag (31) for accommodating excreta which leaks out when a blowout occurs is prepared. A first opening (33) which is opened in the auxiliary accommodation bag is connected to the attachment means, a second opening (35) which is opened in the auxiliary accommodation bag is connected to the face plate, and the auxiliary accommodation bag thereby covers and enwraps the take-in hole. The blown-out excreta which leaks from the take-in hole is accommodated in the auxiliary accommodation bag thereby preventing external scattering of the excreta.
