There are provided a message processing device and a method improved to store a plenty of messages used for processing. When a message is transmitted to another node for providing a service, a message processing unit (26) monitors the message transferred and stores it in a storage region whose allocation is released when the remaining memory amount has become little. When an error has occurred in the processing of a service providing unit (200), the message processing unit (26) stores the error type and a session identifier associated with it. When a message transmission is requested from outside and the error type, the session identifier, and a message associated with them are stored, the message processing unit (26) transmits them. If the storage region which was containing a message is released and no message exists, the message processing unit (26) transmits the other two items.