A log data processing system comprising: a supervisory control device configured to execute an application and generate log data corresponding to the executed application executed; a log data processing server configured to generate and store a log data message based on the generated log data, the log data processing server comprising: a communication unit configured to receive log data information related to the generated log data from the supervisory control device ; a control unit comprising a log message generation unit configured to generate a log message based on the received log data information; and a storage unit configured to store the generated log message and generation history information of the generated log message, wherein the log data information comprises a log message parameter, message code information, and identifier information of the executed application, wherein the log message comprises a level character string and a message character string; and wherein the system is characterised in that the log message generation unit is further configured to: generate the level character string and level information of the log data based on the message code information, and generate the message character string by replacing the log message parameter with a message-type parameter value. a supervisory control device configured to execute an application and generate log data corresponding to the executed application executed; a log data processing server configured to generate and store a log data message based on the generated log data, the log data processing server comprising: a communication unit configured to receive log data information related to the generated log data from the supervisory control device ; a control unit comprising a log message generation unit configured to generate a log message based on the received log data information; and a storage unit configured to store the generated log message and generation history information of the generated log message, a communication unit configured to receive log data information related to the generated log data from the supervisory control device ; a control unit comprising a log message generation unit configured to generate a log message based on the received log data information; and a storage unit configured to store the generated log message and generation history information of the generated log message, wherein the log data information comprises a log message parameter, message code information, and identifier information of the executed application, wherein the log message comprises a level character string and a message character string; and wherein the system is characterised in that the log message generation unit is further configured to: generate the level character string and level information of the log data based on the message code information, and generate the message character string by replacing the log message parameter with a message-type parameter value. the log message comprises a level character string and a message character string; and wherein the system is characterised in that the log message generation unit is further configured to: generate the level character string and level information of the log data based on the message code information, and generate the message character string by replacing the log message parameter with a message-type parameter value. generate the level character string and level information of the log data based on the message code information, and generate the message character string by replacing the log message parameter with a message-type parameter value. <EOS>