We present a case of an 8-year-old boy suffering from sudden-onset severe chest pain and cardiogenic shock due to cardiac tamponade caused by erosion of a Figulla Flex II device. His symptoms developed 4 days after transcatheter closure of an atrial septal defect. After emergent pericardiocentesis, surgery was performed to remove the device, close the atrial septal defect, and repair the laceration in the anterior-superior wall of the right atrium and the perforation on the aortic wall adjacent to the right atrial free wall perforation site. All surgical procedures were successful, and the patient was discharged without sequelae. Although there have been few reports on the erosion of this flexible device, a lethal complication can occur when the right-sided disc of the oversized device impinges perpendicularly on the aortic wall.