A breathing sensing device that detects breathing of a subject, the breathing sensing device including a film-shaped sensor configured to adhere to a body surface of the subject from a region corresponding to a xiphoid process of a sternum of the subject to a region corresponding to an epigastrium of the subject. The sensor is configured to detect the breathing of the subject by detecting relative positional changes between the region corresponding to the xiphoid process and the region corresponding to the epigastrium.