A communication apparatus of the embodiment is provided with a first IF card that performs a relay process of a data frame in a first direction of a ring network, a second IF card that performs a relay process of a data frame in a second direction of the ring network, a communication-status determination unit that monitors the communication status from the first IF card to the second IF card, a block control unit that sets a new block point to either the first IF card or the second IF card when the communication status is abnormal, and a ring protocol processor that notifies other communication apparatuses that constitute the ring network of information for notifying the switching of a block point in the ring network, which indicates that the new block point has been set.