Abstract: A node device provided on a network has a log-information storage unit in which log information on the node device is stored, a control unit that performs processing of producing the log information during operation to store the log information in the log-information storage unit, a first sending and receiving unit that receives data from an outside of the node device and to send data to the outside of the node device, and a log processing unit that receives the data from the outside of the node device through the first sending and receiving unit and to perform processing of reading the log information from the log-information storage unit to cause the first sending and receiving unit to send the log information irrespective of the control unit when the received data comprises a log request command expressing a request for the log information.