Troubles with the inspiratory limb have been noted with the reuse of the Mera-F Circuit. However, to our knowledge there have been no reports of the mishap in socket that is made of polycarbonate material. The case we present is a mishap due to the fracture of socket with the reuse of the circuit under general anesthesia. After the operation, the breaks were discovered in four of six other circuits reused. Although the cause of the break is unknown, it is speculated that enflurane or ethylene oxide gas may impair the polycarbonate material. Clinically, we recommend that Mera-F Circuit should be inspected carefully before its reuse.