In personal computer environment, it is important to protect the information leakage. In this paper, a mechanism of protecting information leakage is proposed. This mechanism has two functions. One function is the function of tracing classified information. The other function is the function of controlling the write function. The tracing function is deployed by hook the call of file operations, interprocess communication, and process creation. This paper describes a method that improve the accuracy of tracing classified information and reduce the labor of configuration. This paper shows the proposed mechanism can trace all files and improve the the accuracy of tracing classified information by using the user judgement.