PURPOSE: To provide a bridge device which can surely delete the frame returned after a round of a ring-shaped LAN at an extremely high speed even in a translation system.

CONSTITUTION: A microprocessor 101 converts the contents of each field of a frame received from a bus type LAN 10 into the contents of the corresponding field of an FDDI ring frame. When this converted frame is sent to an FDDI ring 1, an GA detector 107 detects the transmitter address of the frame. This address is registered into a FIFO memory 109. When the frame is received from the ring 1, an SA detector 108 detects the transmitter address of the frame. A comparator 114 compares the detected address with the transmitter address that is designated by a read pointer and registered most previously into the memory 109. When the coincidence is confirmed between both addresses, the read pointer is updated and at the same time the received frame is deleted by a frame deleting circuit 115.