Abstract: Clerical error is a common problem in patent examination. Errors in Patent application document are often caused by the carelessness of applicants. Applicants always claim that these errors are obvious clerical errors, so that they should be allowed to correct or clarify them by proper modification. However, not all errors caused by writing mistakes can be determined as obvious clerical errors. This paper discussed specific errors which should be determined as obvious clerical errors in patent examining practice, by analyzing a typical case.

Key words: patent, error, obvious clerical errors