A thermoluminescence dosimeter has been used practically for personal monitoring of X-γ rays in our institute over two years. In this report, the dosimeter instrumentations are briefly outlined and the procedures to obtain a reliable estimation for each personal dose are mainly discussed. The results obtained are summarized and some of them are compared with those obtained by film badges. It was effective for accurate estimation to use the correction factors determined for individual elements. Careful treatments as described in this paper are necessary to perform the personal monitoring with an accuracy of 1 mrem per 2 weeks.