The thermoluminescent dosimeter is the most commonly used instrument for measuring radiation dose. Based on the previous study that the glow curve changes in the magnetic field environment of a thermal luminescence dose device, the change of the glow curve according to the change of the magnetic field strength is evaluated. Accordingly, the change in the glow curve was analyzed by irradiating 0.5-2 cGy to the thermoluminescent chips with a radiation generator while changing the magnetic field strength using a permanent magnet. As a result of the evaluation, an average increase of 0.3% was observed at 90~120 ℃, an average decrease of -10.6% at 120-160 ℃, and an average increase of 3.2% at 160-260 ℃. Therefore, when applying the thermoluminescent dosimeter, it is necessary to evaluate the dose considering the error rate according to the magnetic field strength.