Disclosed herein are log information collection methods for collecting log information of a network device operating in accordance with instructions from an operation apparatus. In some cases, the log information collection method can comprise: determining whether another piece of the log information including a second character string occurs in a predetermined duration, wherein the niece of log, information includes a first character string; generating a new piece of log information including a third character string; and accepting specifications of the first, second, and third character strings, the predetermined duration, and occurrence or non-occurrence of the piece of the log information and the other piece of the log information.